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Knauss ZT, Hearn CJ, Hendryx NC, Aboalrob FS, Mueller-Figueroa Y, Damron DS, Lewis SJ, Mueller D. Fentanyl-induced reward seeking is sex and dose dependent and is prevented by D-cysteine ethylester. Front Pharmacol 2023; 14:1241578. [PMID: 37795030 PMCID: PMC10546209 DOI: 10.3389/fphar.2023.1241578] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 09/06/2023] [Indexed: 10/06/2023] Open
Abstract
Introduction: Despite their inclination to induce tolerance, addictive states, and respiratory depression, synthetic opioids are among the most effective clinically administered drugs to treat severe acute/chronic pain and induce surgical anesthesia. Current medical interventions for opioid-induced respiratory depression (OIRD), wooden chest syndrome, and opioid use disorder (OUD) show limited efficacy and are marked by low success in the face of highly potent synthetic opioids such as fentanyl. D-Cysteine ethylester (D-CYSee) prevents OIRD and post-treatment withdrawal in male/female rats and mice with minimal effect on analgesic status. However, the potential aversive or rewarding effects of D-CYSee have yet to be fully characterized and its efficacy could be compromised by interactions with opioid-reward pathology. Methods: Using a model of fentanyl-induced conditioned place preference (CPP), this study evaluated 1) the dose and sex dependent effects of fentanyl to induce rewarding states, and 2) the extent to which D-CYSee alters affective state and the acquisition of fentanyl-induced seeking behaviors. Results: Fentanyl reward-related effects were found to be dose and sex dependent. Male rats exhibited a range-bound dose response centered at 5 µg/kg. Female rats exhibited a CPP only at 50 µg/kg. This dose was effective in 25% of females with the remaining 75% showing no significant CPP at any dose. Pretreatment with 100 mg/kg, but not 10 mg/kg, D-CYSee prevented acquisition of fentanyl seeking in males while both doses were effective at preventing acquisition in females. Discussion: These findings suggest that D-CYSee is an effective co-treatment with prescribed opioids to reduce the development of OUD.
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Affiliation(s)
- Zackery T. Knauss
- Department of Biological Sciences, Kent State University, Kent, OH, United States
| | - Caden J. Hearn
- Department of Biological Sciences, Kent State University, Kent, OH, United States
| | - Nathan C. Hendryx
- Department of Biological Sciences, Kent State University, Kent, OH, United States
| | - Fanan S. Aboalrob
- Department of Biological Sciences, Kent State University, Kent, OH, United States
| | | | - Derek S. Damron
- Department of Biological Sciences, Kent State University, Kent, OH, United States
| | - Stephen J. Lewis
- Department of Pediatrics, Division of Pulmonology, Allergy, and Immunology, Case Western Reserve University, Cleveland, OH, United States
| | - Devin Mueller
- Department of Biological Sciences, Kent State University, Kent, OH, United States
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Bosma KJ, Ghosh M, Andrei SR, Zhong L, Dunn JC, Ricciardi VF, Burkett JB, Hatzopoulos AK, Damron DS, Gannon M. Pharmacological modulation of prostaglandin E 2 (PGE 2 ) EP receptors improves cardiomyocyte function under hyperglycemic conditions. Physiol Rep 2022; 10:e15212. [PMID: 35403369 PMCID: PMC8995713 DOI: 10.14814/phy2.15212] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 02/04/2022] [Accepted: 02/06/2022] [Indexed: 06/14/2023] Open
Abstract
Type 2 diabetes (T2D) affects >30 million Americans and nearly 70% of individuals with T2D will die from cardiovascular disease (CVD). Circulating levels of the inflammatory signaling lipid, prostaglandin E2 (PGE2 ), are elevated in the setting of obesity and T2D and are associated with decreased cardiac function. The EP3 and EP4 PGE2 receptors have opposing actions in several tissues, including the heart: overexpression of EP3 in cardiomyocytes impairs function, while EP4 overexpression improves function. Here we performed complementary studies in vitro with isolated cardiomyocytes and in vivo using db/db mice, a model of T2D, to analyze the effects of EP3 inhibition or EP4 activation on cardiac function. Using echocardiography, we found that 2 weeks of systemic treatment of db/db mice with 20 mg/kg of EP3 antagonist, beginning at 6 weeks of age, improves ejection fraction and fractional shortening (with no effect on heart rate). We further show that either EP3 blockade or EP4 activation enhances contractility and calcium cycling in isolated mouse cardiomyocytes cultured in both normal and high glucose. Thus, peak [Ca2+ ]I transient amplitude was increased, while time to peak [Ca2+ ]I and [Ca2+ ]I decay were decreased. These data suggest that modulation of EP3 and EP4 activity has beneficial effects on cardiomyocyte contractility and overall heart function.
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Affiliation(s)
- Karin J. Bosma
- Department of Veterans Affairs Tennessee Valley AuthorityNashvilleTennesseeUSA
- Department of MedicineVanderbilt University Medical CenterNashvilleTennesseeUSA
| | - Monica Ghosh
- Department of Biological SciencesSchool of Biomedical SciencesKent State UniversityKentOhioUSA
| | - Spencer R. Andrei
- Department of Veterans Affairs Tennessee Valley AuthorityNashvilleTennesseeUSA
- Department of MedicineVanderbilt University Medical CenterNashvilleTennesseeUSA
| | - Lin Zhong
- Department of MedicineVanderbilt University Medical CenterNashvilleTennesseeUSA
| | - Jennifer C. Dunn
- Department of Veterans Affairs Tennessee Valley AuthorityNashvilleTennesseeUSA
- Department of MedicineVanderbilt University Medical CenterNashvilleTennesseeUSA
| | | | - Juliann B. Burkett
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityNashvilleTennesseeUSA
| | - Antonis K. Hatzopoulos
- Department of MedicineVanderbilt University Medical CenterNashvilleTennesseeUSA
- Department of Cell and Developmental BiologyVanderbilt UniversityNashvilleTennesseeUSA
| | - Derek S. Damron
- Department of Biological SciencesSchool of Biomedical SciencesKent State UniversityKentOhioUSA
| | - Maureen Gannon
- Department of Veterans Affairs Tennessee Valley AuthorityNashvilleTennesseeUSA
- Department of MedicineVanderbilt University Medical CenterNashvilleTennesseeUSA
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityNashvilleTennesseeUSA
- Department of Cell and Developmental BiologyVanderbilt UniversityNashvilleTennesseeUSA
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Baby SM, Discala JF, Gruber R, Getsy PM, Cheng F, Damron DS, Lewis SJ. Tempol Reverses the Negative Effects of Morphine on Arterial Blood-Gas Chemistry and Tissue Oxygen Saturation in Freely-Moving Rats. Front Pharmacol 2021; 12:749084. [PMID: 34630119 PMCID: PMC8493249 DOI: 10.3389/fphar.2021.749084] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/03/2021] [Indexed: 12/14/2022] Open
Abstract
We have reported that pretreatment with the clinically approved superoxide dismutase mimetic, Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl), blunts the cardiorespiratory depressant responses elicited by a subsequent injection of fentanyl, in halothane-anesthetized rats. The objective of the present study was to determine whether Tempol is able to reverse the effects of morphine on arterial blood-gas (ABG) chemistry in freely-moving Sprague Dawley rats. The intravenous injection of morphine (10 mg/kg) elicited substantial decreases in pH, pO2 and sO2 that were accompanied by substantial increases in pCO2 and Alveolar-arterial gradient, which results in diminished gas-exchange within the lungs. Intravenous injection of a 60 mg/kg dose of Tempol 15 min after the injection of morphine caused minor improvements in pO2 and pCO2 but not in other ABG parameters. In contrast, the 100 mg/kg dose of Tempol caused an immediate and sustained reversal of the negative effects of morphine on arterial blood pH, pCO2, pO2, sO2 and Alveolar-arterial gradient. In other rats, we used pulse oximetry to determine that the 100 mg/kg dose of Tempol, but not the 60 mg/kg dose elicited a rapid and sustained reversal of the negative effects of morphine (10 mg/kg, IV) on tissue O2 saturation (SpO2). The injection of morphine caused a relatively minor fall in mean arterial blood pressure that was somewhat exacerbated by Tempol. These findings demonstrate that Tempol can reverse the negative effects of morphine on ABG chemistry in freely-moving rats paving the way of structure-activity and mechanisms of action studies with the host of Tempol analogues that are commercially available.
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Affiliation(s)
| | | | - Ryan Gruber
- Galleon Pharmaceuticals Inc, Horsham, PA, United states
| | - Paulina M Getsy
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United states
| | - Feixiong Cheng
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United states
| | - Derek S Damron
- Department of Biological Sciences, School of Biomedical Sciences, Kent State University, Kent, OH, United states
| | - Stephen J Lewis
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United states.,Department of Pharmacology, Case Western Reserve University, Cleveland, OH, United states
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Ghosh M, Schepetkin IA, Özek G, Özek T, Khlebnikov AI, Damron DS, Quinn MT. Essential Oils from Monarda fistulosa: Chemical Composition and Activation of Transient Receptor Potential A1 (TRPA1) Channels. Molecules 2020; 25:molecules25214873. [PMID: 33105614 PMCID: PMC7659962 DOI: 10.3390/molecules25214873] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 10/18/2020] [Accepted: 10/19/2020] [Indexed: 12/11/2022] Open
Abstract
Little is known about the pharmacological activity of Monarda fistulosa L. essential oils. To address this issue, we isolated essential oils from the flowers and leaves of M. fistulosa and analyzed their chemical composition. We also analyzed the pharmacological effects of M. fistulosa essential oils on transient receptor potential (TRP) channel activity, as these channels are known targets of various essential oil constituents. Flower (MEOFl) and leaf (MEOLv) essential oils were comprised mainly of monoterpenes (43.1% and 21.1%) and oxygenated monoterpenes (54.8% and 77.7%), respectively, with a high abundance of monoterpene hydrocarbons, including p-cymene, γ-terpinene, α-terpinene, and α-thujene. Major oxygenated monoterpenes of MEOFl and MEOLv included carvacrol and thymol. Both MEOFl and MEOLv stimulated a transient increase in intracellular free Ca2+ concentration ([Ca2+]i) in TRPA1 but not in TRPV1 or TRPV4-transfected cells, with MEOLv being much more effective than MEOFl. Furthermore, the pure monoterpenes carvacrol, thymol, and β-myrcene activated TRPA1 but not the TRPV1 or TRPV4 channels, suggesting that these compounds represented the TRPA1-activating components of M. fistulosa essential oils. The transient increase in [Ca2+]i induced by MEOFl/MEOLv, carvacrol, β-myrcene, and thymol in TRPA1-transfected cells was blocked by a selective TRPA1 antagonist, HC-030031. Although carvacrol and thymol have been reported previously to activate the TRPA1 channels, this is the first report to show that β-myrcene is also a TRPA1 channel agonist. Finally, molecular modeling studies showed a substantial similarity between the docking poses of carvacrol, thymol, and β-myrcene in the binding site of human TRPA1. Thus, our results provide a cellular and molecular basis to explain at least part of the therapeutic properties of these essential oils, laying the foundation for prospective pharmacological studies involving TRP ion channels.
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Affiliation(s)
- Monica Ghosh
- Department of Biological Sciences, School of Biological Sciences, Kent State University, Kent, OH 44242, USA; (M.G.); (D.S.D.)
| | - Igor A. Schepetkin
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA;
| | - Gulmira Özek
- Department of Pharmacognosy, Faculty of Pharmacy, Anadolu University, 26470 Eskisehir, Turkey; (G.Ö.); (T.Ö.)
| | - Temel Özek
- Department of Pharmacognosy, Faculty of Pharmacy, Anadolu University, 26470 Eskisehir, Turkey; (G.Ö.); (T.Ö.)
- Medicinal Plant, Drug and Scientific Research and Application Center (AUBIBAM), Anadolu University, 26470 Eskişehir, Turkey
| | - Andrei I. Khlebnikov
- National Research Tomsk Polytechnic University, Tomsk 643050, Russia;
- Faculty of Chemistry, Tomsk State University, 634050 Tomsk, Russia
| | - Derek S. Damron
- Department of Biological Sciences, School of Biological Sciences, Kent State University, Kent, OH 44242, USA; (M.G.); (D.S.D.)
| | - Mark T. Quinn
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA;
- Correspondence: ; Tel.: +1-406-994-4707; Fax: +1-406-994-4303
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Andrei SR, Ghosh M, Sinharoy P, Damron DS. Stimulation of TRPA1 attenuates ischemia-induced cardiomyocyte cell death through an eNOS-mediated mechanism. Channels (Austin) 2020; 13:192-206. [PMID: 31161862 PMCID: PMC6557600 DOI: 10.1080/19336950.2019.1623591] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The functional expression of transient receptor potential cation channel of the ankyrin-1 subtype (TRPA1) has recently been identified in adult mouse cardiac tissue where stimulation of this ion channel leads to increases in adult mouse ventricular cardiomyocyte (CM) contractile function via a Ca2+-Calmodulin-dependent kinase (CaMKII) pathway. However, the extent to which TRPA1 induces nitric oxide (NO) production in CMs, and whether this signaling cascade mediates physiological or pathophysiological events in cardiac tissue remains elusive. Freshly isolated CMs from wild-type (WT) or TRPA1 knockout (TRPA1-/-) mouse hearts were treated with AITC (100 µM) and prepared for immunoblot, NO detection or ischemia protocols. Our findings demonstrate that TRPA1 stimulation with AITC results in phosphorylation of protein kinase B (Akt) and endothelial NOS (eNOS) concomitantly with NO production in a concentration- and time-dependent manner. Additionally, we found that TRPA1 induced increases in CM [Ca2+]i and contractility occur independently of Akt and eNOS activation mechanisms. Further analysis revealed that the presence and activation of TRPA1 promotes CM survival and viability following ischemic insult via a mechanism partially dependent upon eNOS. Therefore, activation of the TRPA1/Akt/eNOS pathway attenuates ischemia-induced CM cell death.
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Affiliation(s)
- Spencer R Andrei
- a Department of Medicine , Vanderbilt University Medical Center , Nashville , TN , USA
| | - Monica Ghosh
- b Department of Biomedical Sciences , Kent State University , Kent , OH , USA
| | - Pritam Sinharoy
- c Department of Biopharmaceutical Development , Medimmune LLC , Gaithersburg , MD , USA
| | - Derek S Damron
- b Department of Biomedical Sciences , Kent State University , Kent , OH , USA
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Abstract
Transient receptor potential cation channel, subfamily A, member 1 (TRPA1), is activated by a broad range of noxious stimuli. Cdk5, a member of the Cdk family, has recently been identified as a modulator of pain signaling pathways. In the current study, we investigated the extent to which Cdk5 modulates TRPA1 activity. Cdk5 inhibition was found to attenuate TRPA1 response to agonist in mouse DRG sensory neurons. Additionally, the presence of active Cdk5 was associated with increased TRPA1 phosphorylation in transfected HEK293 cells that was roscovitine-sensitive and absent in the mouse mutant S449A full-length channel. Immunopurified Cdk5 was observed to phosphorylate human TRPA1 peptide substrate at S448A in vitro. Our results point to a role for Cdk5 in modulating TRPA1 activity.
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Affiliation(s)
- Michael A Sulak
- a Department of Human Genetics , University of Chicago , Chicago , IL , USA
| | - Monica Ghosh
- b Department of Biological Sciences , Kent State University , Kent , OH , USA
| | - Pritam Sinharoy
- c Department of Anesthesia , Perioperative and Pain Medicine, Stanford School of Medicine , Stanford , CA , USA
| | - Spencer R Andrei
- d Department of Medicine , Vanderbilt University Medical Center , Nashville , TN , USA
| | - Derek S Damron
- b Department of Biological Sciences , Kent State University , Kent , OH , USA
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7
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Andrei SR, Ghosh M, Sinharoy P, Dey S, Bratz IN, Damron DS. TRPA1 ion channel stimulation enhances cardiomyocyte contractile function via a CaMKII-dependent pathway. Channels (Austin) 2017; 11:587-603. [PMID: 28792844 DOI: 10.1080/19336950.2017.1365206] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
RATIONALE Transient receptor potential channels of the ankyrin subtype-1 (TRPA1) are non-selective cation channels that show high permeability to calcium. Previous studies from our laboratory have demonstrated that TRPA1 ion channels are expressed in adult mouse ventricular cardiomyocytes (CMs) and are localized at the z-disk, costamere and intercalated disk. The functional significance of TRPA1 ion channels in the modulation of CM contractile function have not been explored. OBJECTIVE To identify the extent to which TRPA1 ion channels are involved in modulating CM contractile function and elucidate the cellular mechanism of action. METHODS AND RESULTS Freshly isolated CMs were obtained from murine heart and loaded with Fura-2 AM. Simultaneous measurement of intracellular free Ca2+ concentration ([Ca2+]i) and contractility was performed in individual CMs paced at 0.3 Hz. Our findings demonstrate that TRPA1 stimulation with AITC results in a dose-dependent increase in peak [Ca2+]i and a concomitant increase in CM fractional shortening. Further analysis revealed a dose-dependent acceleration in time to peak [Ca2+]i and velocity of shortening as well as an acceleration in [Ca2+]i decay and velocity of relengthening. These effects of TRPA1 stimulation were not observed in CMs pre-treated with the TRPA1 antagonist, HC-030031 (10 µmol/L) nor in CMs obtained from TRPA1-/- mice. Moreover, we observed no significant increase in cAMP levels or PKA activity in response to TRPA1 stimulation and the PKA inhibitor peptide (PKI 14-22; 100 nmol/L) failed to have any effect on the TRPA1-mediated increase in CM contractile function. However, TRPA1 stimulation resulted in a rapid phosphorylation of Ca2+/calmodulin-dependent kinase II (CaMKII) (1-5 min) that correlated with increases in CM [Ca2+]i and contractile function. Finally, all aspects of TRPA1-dependent increases in CM [Ca2+]i, contractile function and CaMKII phosphorylation were virtually abolished by the CaMKII inhibitors, KN-93 (10 µmol/L) and autocamtide-2-related peptide (AIP; 20 µmol/L). CONCLUSIONS These novel findings demonstrate that stimulation of TRPA1 ion channels in CMs results in activation of a CaMKII-dependent signaling pathway resulting in modulation of intracellular Ca2+ availability and handling leading to increases in CM contractile function. Cardiac TRPA1 ion channels may represent a novel therapeutic target for increasing the inotropic and lusitropic state of the heart.
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Affiliation(s)
- Spencer R Andrei
- a Department of Medicine , Vanderbilt University Medical Center , Nashville , TN , USA
| | - Monica Ghosh
- b Department of Biological Sciences , Kent State University , Kent , OH , USA
| | - Pritam Sinharoy
- c Department of Anesthesia , Perioperative and Pain Medicine, Stanford School of Medicine , Stanford , CA , USA
| | - Souvik Dey
- b Department of Biological Sciences , Kent State University , Kent , OH , USA
| | - Ian N Bratz
- d Department of Integrated Medical Sciences , Northeast Ohio Medical University , Rootstown , OH , USA
| | - Derek S Damron
- b Department of Biological Sciences , Kent State University , Kent , OH , USA
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Sinharoy P, Bratz IN, Sinha S, Showalter LE, Andrei SR, Damron DS. TRPA1 and TRPV1 contribute to propofol-mediated antagonism of U46619-induced constriction in murine coronary arteries. PLoS One 2017; 12:e0180106. [PMID: 28644897 PMCID: PMC5482493 DOI: 10.1371/journal.pone.0180106] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 06/09/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Transient receptor potential (TRP) ion channels have emerged as key components contributing to vasoreactivity. Propofol, an anesthetic is associated with adverse side effects including hypotension and acute pain upon infusion. Our objective was to determine the extent to which TRPA1 and/or TRPV1 ion channels are involved in mediating propofol-induced vasorelaxation of mouse coronary arterioles in vitro and elucidate the potential cellular signal transduction pathway by which this occurs. METHODS Hearts were excised from anesthetized mice and coronary arterioles were dissected from control C57Bl/6J, TRPA1-/-, TRPV1-/- and double-knockout mice (TRPAV-/-). Isolated microvessels were cannulated and secured in a temperature-controlled chamber and allowed to equilibrate for 1 hr. Vasoreactivity studies were performed in microvessels pre-constricted with U46619 to assess the dose-dependent relaxation effects of propofol on coronary microvascular tone. RESULTS Propofol-induced relaxation was unaffected in vessels obtained from TRPV1-/- mice, markedly attenuated in pre-constricted vessels obtained from TRPA1-/- mice and abolished in vessels obtained from TRPAV-/- mice. Furthermore, NOS inhibition with L-NAME or endothelium denuding abolished the proporfol-induced depressor response in pre-constricted vessels obtained from all mice. In the absence of L-NAME, BKCa inhibition with penitrem A markedly attenuated propofol-mediated relaxation in vessels obtained from wild-type mice and to a lesser extent in vessels obtained from TRPV1-/-, mice with no effect in vessels obtained from TRPA1-/- or TRPAV-/- mice. CONCLUSIONS TRPA1 and TRPV1 appear to contribute to the propofol-mediated antagonism of U46619-induced constriction in murine coronary microvessels that involves activation of NOS and BKCa.
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Affiliation(s)
- Pritam Sinharoy
- Department of Anesthesia, Perioperative and Pain Medicine, Stanford School of Medicine, Stanford, California, United States of America
| | - Ian N. Bratz
- Department of Integrative Medical Sciences, Northeast Ohio Medical College, Rootstown, Ohio, United States of America
| | - Sayantani Sinha
- Department of Surgery, Division of Orthopedic Surgery, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Loral E. Showalter
- Department of Biological Sciences, Kent State University, Kent, Ohio, United States of America
| | - Spencer R. Andrei
- Department of Biological Sciences, Kent State University, Kent, Ohio, United States of America
| | - Derek S. Damron
- Department of Biological Sciences, Kent State University, Kent, Ohio, United States of America
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Özek G, Schepetkin IA, Utegenova GA, Kirpotina LN, Andrei SR, Özek T, Başer KHC, Abidkulova KT, Kushnarenko SV, Khlebnikov AI, Damron DS, Quinn MT. Chemical composition and phagocyte immunomodulatory activity of Ferula iliensis essential oils. J Leukoc Biol 2017; 101:1361-1371. [PMID: 28258152 DOI: 10.1189/jlb.3a1216-518rr] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 02/08/2017] [Accepted: 02/10/2017] [Indexed: 12/29/2022] Open
Abstract
Essential oil extracts from Ferula iliensis have been used traditionally in Kazakhstan for treatment of inflammation and other illnesses. Because little is known about the biologic activity of these essential oils that contributes to their therapeutic properties, we analyzed their chemical composition and evaluated their phagocyte immunomodulatory activity. The main components of the extracted essential oils were (E)-propenyl sec-butyl disulfide (15.7-39.4%) and (Z)-propenyl sec-butyl disulfide (23.4-45.0%). Ferula essential oils stimulated [Ca2+]i mobilization in human neutrophils and activated ROS production in human neutrophils and murine bone marrow phagocytes. Activation of human neutrophil [Ca2+]i flux by Ferula essential oils was dose-dependently inhibited by capsazepine, a TRPV1 channel antagonist, indicating that TRPV1 channels mediate this response. Furthermore, Ferula essential oils stimulated Ca2+ influx in TRPV1 channel-transfected HEK293 cells and desensitized the capsaicin-induced response in these cells. Additional molecular modeling with known TRPV1 channel agonists suggested that the active component is likely to be (Z)-propenyl sec-butyl disulfide. Our results provide a cellular and molecular basis to explain at least part of the beneficial therapeutic properties of FEOs.
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Affiliation(s)
- Gulmira Özek
- Department of Pharmacognosy, Faculty of Pharmacy, Anadolu University, Eskisehir, Turkey
| | - Igor A Schepetkin
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Gulzhakhan A Utegenova
- Institute of Plant Biology and Biotechnology, Almaty, Republic of Kazakhstan.,Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Republic of Kazakhstan
| | - Liliya N Kirpotina
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Spencer R Andrei
- Department of Biological Sciences, Kent State University, Kent, Ohio, USA
| | - Temel Özek
- Department of Pharmacognosy, Faculty of Pharmacy, Anadolu University, Eskisehir, Turkey
| | - Kemal Hüsnü Can Başer
- Department of Pharmacognosy, Faculty of Pharmacy, Near East University, Nicosia, North Cyprus
| | - Karime T Abidkulova
- Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, Republic of Kazakhstan
| | | | - Andrei I Khlebnikov
- Department of Biotechnology and Organic Chemistry, Tomsk Polytechnic University, Tomsk, Russia; and.,Department of Chemistry, Altai State Technical University, Barnaul, Russia
| | - Derek S Damron
- Department of Biological Sciences, Kent State University, Kent, Ohio, USA
| | - Mark T Quinn
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA;
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10
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DelloStritto DJ, Sinharoy P, Connell PJ, Fahmy JN, Cappelli HC, Thodeti CK, Geldenhuys WJ, Damron DS, Bratz IN. 4-Hydroxynonenal dependent alteration of TRPV1-mediated coronary microvascular signaling. Free Radic Biol Med 2016; 101:10-19. [PMID: 27682362 PMCID: PMC5490661 DOI: 10.1016/j.freeradbiomed.2016.09.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 09/14/2016] [Accepted: 09/23/2016] [Indexed: 01/11/2023]
Abstract
We demonstrated previously that TRPV1-dependent regulation of coronary blood flow (CBF) is disrupted in diabetes. Further, we have shown that endothelial TRPV1 is differentially regulated, ultimately leading to the inactivation of TRPV1, when exposed to a prolonged pathophysiological oxidative environment. This environment has been shown to increase lipid peroxidation byproducts including 4-Hydroxynonenal (4-HNE). 4-HNE is notorious for producing protein post-translation modification (PTM) via reactions with the amino acids: cysteine, histidine and lysine. Thus, we sought to determine if 4-HNE mediated post-translational modification of TRPV1 could account for dysfunctional TRPV1-mediated signaling observed in diabetes. Our initial studies demonstrate 4-HNE infusion decreases TRPV1-dependent coronary blood flow in C57BKS/J (WT) mice. Further, we found that TRPV1-dependent vasorelaxation was suppressed after 4-HNE treatment in isolated mouse coronary arterioles. Moreover, we demonstrate 4-HNE significantly inhibited TRPV1 currents and Ca2+ entry utilizing patch-clamp electrophysiology and calcium imaging respectively. Using molecular modeling, we identified potential pore cysteines residues that, when mutated, could restore TRPV1 function in the presence of 4-HNE. Specifically, complete rescue of capsaicin-mediated activation of TRPV1 was obtained following mutation of pore Cysteine 621. Finally, His tag pull-down of TRPV1 in HEK cells treated with 4-HNE demonstrated a significant increase in 4-HNE binding to TRPV1, which was reduced in the TRPV1 C621G mutant. Taken together these data suggest that 4-HNE decreases TRPV1-mediated responses, at both the in vivo and in vitro levels and this dysfunction can be rescued via mutation of the pore Cysteine 621. Our results show the first evidence of an amino acid specific modification of TRPV1 by 4-HNE suggesting this 4-HNE-dependent modification of TRPV1 may contribute to microvascular dysfunction and tissue perfusion deficits characteristic of diabetes.
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Affiliation(s)
- Daniel J DelloStritto
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 St. Rt. 44, Rootstown, OH 44272, USA.
| | - Pritam Sinharoy
- Department of Biological Sciences, Kent State University, 256 Cunningham Hall, Kent, OH 44242, USA.
| | - Patrick J Connell
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 St. Rt. 44, Rootstown, OH 44272, USA.
| | - Joseph N Fahmy
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 St. Rt. 44, Rootstown, OH 44272, USA.
| | - Holly C Cappelli
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 St. Rt. 44, Rootstown, OH 44272, USA; Department of Biomedical Sciences, Kent State University, 256 Cunningham Hall, Kent, OH 44242, USA.
| | - Charles K Thodeti
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 St. Rt. 44, Rootstown, OH 44272, USA.
| | - Werner J Geldenhuys
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, P.O. Box 9500, Morgantown, WV 26506, USA.
| | - Derek S Damron
- Department of Biological Sciences, Kent State University, 256 Cunningham Hall, Kent, OH 44242, USA.
| | - Ian N Bratz
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 St. Rt. 44, Rootstown, OH 44272, USA.
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11
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Schepetkin IA, Kushnarenko SV, Özek G, Kirpotina LN, Sinharoy P, Utegenova GA, Abidkulova KT, Özek T, Başer KHC, Kovrizhina AR, Khlebnikov AI, Damron DS, Quinn MT. Modulation of Human Neutrophil Responses by the Essential Oils from Ferula akitschkensis and Their Constituents. J Agric Food Chem 2016; 64:7156-70. [PMID: 27586050 PMCID: PMC5048753 DOI: 10.1021/acs.jafc.6b03205] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Essential oils were obtained by hydrodistillation of the umbels+seeds and stems of Ferula akitschkensis (FAEOu/s and FAEOstm, respectively) and analyzed by gas chromatography and gas chromatography-mass spectrometry. Fifty-two compounds were identified in FAEOu/s; the primary components were sabinene, α-pinene, β-pinene, terpinen-4-ol, eremophilene, and 2-himachalen-7-ol, whereas the primary components of FAEOstm were myristicin and geranylacetone. FAEOu/s, β-pinene, sabinene, γ-terpinene, geranylacetone, isobornyl acetate, and (E)-2-nonenal stimulated [Ca(2+)]i mobilization in human neutrophils, with the most potent being geranylacetone (EC50 = 7.6 ± 1.9 μM) and isobornyl acetate 6.4 ± 1.7 (EC50 = 7.6 ± 1.9 μM). In addition, treatment of neutrophils with β-pinene, sabinene, γ-terpinene, geranylacetone, and isobornyl acetate desensitized the cells to N-formyl-Met-Leu-Phe (fMLF)- and interleukin-8 (IL-8)-induced [Ca(2+)]i flux and inhibited fMLF-induced chemotaxis. The effects of β-pinene, sabinene, γ-terpinene, geranylacetone, and isobornyl acetate on neutrophil [Ca(2+)]i flux were inhibited by transient receptor potential (TRP) channel blockers. Furthermore, the most potent compound, geranylacetone, activated Ca(2+) influx in TRPV1-transfected HEK293 cells. In contrast, myristicin inhibited neutrophil [Ca(2+)]i flux stimulated by fMLF and IL-8 and inhibited capsaicin-induced Ca(2+) influx in TRPV1-transfected HEK293 cells. These findings, as well as pharmacophore modeling of TRP agonists, suggest that geranylacetone is a TRPV1 agonist, whereas myristicin is a TRPV1 antagonist. Thus, at least part of the medicinal properties of Ferula essential oils may be due to modulatory effects on TRP channels.
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Affiliation(s)
- Igor A Schepetkin
- Department of Microbiology and Immunology, Montana State University , Bozeman, Montana 59717, United States
| | | | - Gulmira Özek
- Department of Pharmacognosy, Faculty of Pharmacy, Anadolu University , Eskisehir 26470, Turkey
| | - Liliya N Kirpotina
- Department of Microbiology and Immunology, Montana State University , Bozeman, Montana 59717, United States
| | - Pritam Sinharoy
- Department of Biological Sciences, Kent State University , Kent, Ohio 44242, United States
| | - Gulzhakhan A Utegenova
- Institute of Plant Biology and Biotechnology , Almaty 050040, Republic of Kazakhstan
- Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University , Almaty 050040, Republic of Kazakhstan
| | - Karime T Abidkulova
- Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University , Almaty 050040, Republic of Kazakhstan
| | - Temel Özek
- Department of Pharmacognosy, Faculty of Pharmacy, Anadolu University , Eskisehir 26470, Turkey
| | - Kemal Hüsnü Can Başer
- Department of Pharmacognosy, Faculty of Pharmacy, Near East University , Nicosia, North Cyprus
| | - Anastasia R Kovrizhina
- Department of Biotechnology and Organic Chemistry, Tomsk Polytechnic University , Tomsk 634050, Russia
| | - Andrei I Khlebnikov
- Department of Biotechnology and Organic Chemistry, Tomsk Polytechnic University , Tomsk 634050, Russia
- Department of Chemistry, Altai State Technical University , Barnaul 656038, Russia
| | - Derek S Damron
- Department of Biological Sciences, Kent State University , Kent, Ohio 44242, United States
| | - Mark T Quinn
- Department of Microbiology and Immunology, Montana State University , Bozeman, Montana 59717, United States
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12
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Andrei SR, Sinharoy P, Bratz IN, Damron DS. TRPA1 is functionally co-expressed with TRPV1 in cardiac muscle: Co-localization at z-discs, costameres and intercalated discs. Channels (Austin) 2016; 10:395-409. [PMID: 27144598 PMCID: PMC4988441 DOI: 10.1080/19336950.2016.1185579] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Transient receptor potential channels of the ankyrin subtype-1 (TRPA1) and vanilloid subtype-1 (TRPV1) are structurally related, non-selective cation channels that show a high permeability to calcium. Previous studies indicate that TRP channels play a prominent role in the regulation of cardiovascular dynamics and homeostasis, but also contribute to the pathophysiology of many diseases and disorders within the cardiovascular system. However, no studies to date have identified the functional expression and/or intracellular localization of TRPA1 in primary adult mouse ventricular cardiomyocytes (CMs). Although TRPV1 has been implicated in the regulation of cardiac function, there is a paucity of information regarding functional expression and localization of TRPV1 in adult CMs. Our current studies demonstrate that TRPA1 and TRPV1 ion channels are co-expressed at the protein level in CMs and both channels are expressed throughout the endocardium, myocardium and epicardium. Moreover, immunocytochemical localization demonstrates that both channels predominantly colocalize at the Z-discs, costameres and intercalated discs. Furthermore, specific TRPA1 and TRPV1 agonists elicit dose-dependent, transient rises in intracellular free calcium concentration ([Ca2+]i) that are abolished in CMs obtained from TRPA1−/− and TRPV1−/− mice. Similarly, we observed a dose-dependent attenuation of the TRPA1 and TRPV1 agonist-induced increase in [Ca2+]i when WT CMs were pretreated with increasing concentrations of selective TRPA1 or TRPV1 channel antagonists. In summary, these findings demonstrate functional expression and the precise ultrastructural localization of TRPA1 and TRPV1 ion channels in freshly isolated mouse CMs. Crosstalk between TRPA1 and TRPV1 may be important in mediating cellular signaling events in cardiac muscle.
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Affiliation(s)
- Spencer R Andrei
- a Department of Biological Sciences , Kent State University , Kent , OH , USA
| | - Pritam Sinharoy
- a Department of Biological Sciences , Kent State University , Kent , OH , USA
| | - Ian N Bratz
- b Department of Integrated Medical Sciences , Northeast Ohio Medical University , Rootstown , OH , USA
| | - Derek S Damron
- a Department of Biological Sciences , Kent State University , Kent , OH , USA
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Sinharoy P, Zhang H, Sinha S, Prudner BC, Bratz IN, Damron DS. Propofol restores TRPV1 sensitivity via a TRPA1-, nitric oxide synthase-dependent activation of PKCε. Pharmacol Res Perspect 2015; 3:e00153. [PMID: 26171233 PMCID: PMC4492729 DOI: 10.1002/prp2.153] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 05/07/2015] [Accepted: 05/11/2015] [Indexed: 12/11/2022] Open
Abstract
We previously demonstrated that the intravenous anesthetic, propofol, restores the sensitivity of transient receptor potential vanilloid channel subtype-1 (TRPV1) receptors via a protein kinase C epsilon (PKCε)-dependent and transient receptor potential ankyrin channel subtype-1 (TRPA1)-dependent pathway in sensory neurons. The extent to which the two pathways are directly linked or operating in parallel has not been determined. Using a molecular approach, our objectives of the current study were to confirm that TRPA1 activation directly results in PKCε activation and to elucidate the cellular mechanism by which this occurs. F-11 cells were transfected with complimentary DNA (cDNA) for TRPV1 only or both TRPV1 and TRPA1. Intracellular Ca(2+) concentration was measured in individual cells via fluorescence microscopy. An immunoblot analysis of the total and phosphorylated forms of PKCε, nitric oxide synthase (nNOS), and TRPV1 was also performed. In F-11 cells containing both channels, PKCε inhibition prevented the propofol- and allyl isothiocyanate (AITC)-induced restoration of TRPV1 sensitivity to agonist stimulation as well as increased phosphorylation of PKCε and TRPV1. In cells containing TRPV1 only, neither agonist induced PKCε or TRPV1 phosphorylation. Moreover, NOS inhibition blocked propofol-and AITC-induced restoration of TRPV1 sensitivity and PKCε phosphorylation, and PKCε inhibition prevented the nitric oxide donor, SNAP, from restoring TRPV1 sensitivity. Also, propofol-and AITC-induced phosphorylation of nNOS and nitric oxide (NO) production were blocked with the TRPA1-antagonist, HC-030031. These data indicate that the AITC- and propofol-induced restoration of TRPV1 sensitivity is mediated by a TRPA1-dependent, nitric oxide synthase-dependent activation of PKCε.
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Affiliation(s)
- Pritam Sinharoy
- Department of Biological Sciences, Kent State University Kent, Ohio, 44242
| | | | - Sayantani Sinha
- Department of Biological Sciences, Kent State University Kent, Ohio, 44242
| | - Bethany C Prudner
- Department of Biological Sciences, Kent State University Kent, Ohio, 44242
| | - Ian N Bratz
- Department of Integrated Medical Sciences, Northeast Ohio Medical University Rootstown, Ohio
| | - Derek S Damron
- Department of Biological Sciences, Kent State University Kent, Ohio, 44242
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14
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Sinha S, Sinharoy P, Bratz IN, Damron DS. Propofol causes vasodilation in vivo via TRPA1 ion channels: role of nitric oxide and BKCa channels. PLoS One 2015; 10:e0122189. [PMID: 25830814 PMCID: PMC4382130 DOI: 10.1371/journal.pone.0122189] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Accepted: 02/10/2015] [Indexed: 11/18/2022] Open
Abstract
Background Transient receptor potential (TRP) ion channels of the A1 (TRPA1) and V1 (TRPV1) subtypes are key regulators of vasomotor tone. Propofol is an intravenous anesthetic known to cause vasorelaxation. Our objectives were to examine the extent to which TRPA1 and/or TRPV1 ion channels mediate propofol-induced depressor responses in vivo and to delineate the signaling pathway(s) involved. Methods Mice were subjected to surgery under 1.5–2.5% sevoflurane gas with supplemental oxygen. After a stable baseline in mean arterial pressure (MAP) was achieved propofol (2.5, 5.0, 10.0 mg/kg/min) was administered to assess the hemodynamic actions of the intravenous anesthetic. The effect of nitric oxide synthase (NOS) inhibition with L-NAME and/or calcium-gated K+ channel (BKCa) inhibition with Penetrim A (Pen A), alone and in combination, on propofol-induced decreases in mean arterial pressure were assessed in control C57Bl/6J, TRPA1-/-, TRPV1-/- and double-knockout mice (TRPAV-/-). Results Propofol decreased MAP in control mice and this effect was markedly attenuated in TRPA1-/- and TRPAV-/- mice but unaffected in TRPV1-/-mice. Moreover, pretreatment with L-NAME or Pen A attenuated the decrease in MAP in control and TRPV1-/- mice, and combined inhibition abolished the depressor response. In contrast, the markedly attenuated propofol-induced depressor response observed in TRPA1-/- and TRPAV-/- mice was unaffected by pre-treatment with Pen A or L-NAME when used either alone or in combination. Conclusion These data demonstrate for the first time that propofol-induced depressor responses in vivo are predominantly mediated by TRPA1 ion channels with no involvement of TRPV1 ion channels and includes activation of both NOS and BKCa channels.
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Affiliation(s)
- Sayantani Sinha
- Department of Biological Sciences, Kent State University, Kent, Ohio, United States of America
| | - Pritam Sinharoy
- Department of Biological Sciences, Kent State University, Kent, Ohio, United States of America
| | - Ian N. Bratz
- Department of Integrative Medical Sciences, Northeast Ohio Medical College, Rootstown, Ohio, United States of America
| | - Derek S. Damron
- Department of Biological Sciences, Kent State University, Kent, Ohio, United States of America
- * E-mail:
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Prudner BC, Damron DS, Russell MA. Beta synemin binds PKA type I upon beta‐adrenergic stimulation in HL‐1 cells. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1041.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Mary A Russell
- Biomedical SciencesKent State University TrumbullWarrenOH
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16
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Kmetz JG, DelloStritto DJ, Sinha S, Prudner B, Damron DS, Bratz IN. ROS‐induced membrane lipid peroxidation impairs TRPV1 channels in the vasculature. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.913.48] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- John G. Kmetz
- Integrative Medical SciencesNortheast Ohio Medical UniversityRootstownOH
| | | | | | | | | | - Ian N. Bratz
- Integrative Medical SciencesNortheast Ohio Medical UniversityRootstownOH
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17
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Guarini G, Ohanyan VA, Kmetz JG, DelloStritto DJ, Thoppil RJ, Thodeti CK, Meszaros JG, Damron DS, Bratz IN. Disruption of TRPV1-mediated coupling of coronary blood flow to cardiac metabolism in diabetic mice: role of nitric oxide and BK channels. Am J Physiol Heart Circ Physiol 2012; 303:H216-23. [PMID: 22610171 DOI: 10.1152/ajpheart.00011.2012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We have previously shown transient receptor potential vanilloid subtype 1 (TRPV1) channel-dependent coronary function is compromised in pigs with metabolic syndrome (MetS). However, the mechanisms through which TRPV1 channels couple coronary blood flow to metabolism are not fully understood. We employed mice lacking TRPV1 [TRPV1((-/-))], db/db diabetic, and control C57BKS/J mice to determine the extent to which TRPV1 channels modulate coronary function and contribute to vascular dysfunction in diabetic cardiomyopathy. Animals were subjected to in vivo infusion of the TRPV1 agonist capsaicin to examine the hemodynamic actions of TRPV1 activation. Capsaicin (1-100 μg·kg(-1)·min(-1)) dose dependently increased coronary blood flow in control mice, which was inhibited by the TRPV1 antagonist capsazepine or the nitric oxide synthase (NOS) inhibitor N-nitro-l-arginine methyl ester (L-NAME). In addition, the capsaicin-mediated increase in blood flow was attenuated in db/db mice. TRPV1((-/-)) mice exhibited no changes in coronary blood flow in response to capsaicin. Vasoreactivity studies in isolated pressurized mouse coronary microvessels revealed a capsaicin-dependent relaxation that was inhibited by the TRPV1 inhibitor SB366791 l-NAME and to the large conductance calcium-sensitive potassium channel (BK) inhibitors iberiotoxin and Penetrim A. Similar to in vivo responses, capsaicin-mediated relaxation was impaired in db/db mice compared with controls. Changes in pH (pH 7.4-6.0) relaxed coronary vessels contracted to the thromboxane mimetic U46619 in all three groups of mice; however, pH-mediated relaxation was blunted in vessels obtained from TRPV1((-/-)) and db/db mice compared with controls. Western blot analysis revealed decreased myocardial TRPV1 protein expression in db/db mice compared with controls. Our data reveal TRPV1 channels mediate coupling of myocardial blood flow to cardiac metabolism via a nitric oxide-dependent, BK channel-dependent pathway that is corrupted in diabetes.
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Affiliation(s)
- Giacinta Guarini
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272, USA
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18
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Sinha S, Kmetz JG, Damron DS, Bratz IN. Propofol regulation of vascular reactivity is mediated via TRP channels. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.1056.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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19
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Ohanyan VA, Guarini G, Thodeti CK, Talasila PK, Raman P, Haney RM, Meszaros JG, Damron DS, Bratz IN. Endothelin-mediated in vivo pressor responses following TRPV1 activation. Am J Physiol Heart Circ Physiol 2011; 301:H1135-42. [DOI: 10.1152/ajpheart.00082.2011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Transient receptor potential vanilliod 1 (TRPV1) channels have recently been postulated to play a role in the vascular complications/consequences associated with diabetes despite the fact that the mechanisms through which TRPV1 regulates vascular function are not fully known. Accordingly, our goal was to define the mechanisms by which TRPV1 channels modulate vascular function and contribute to vascular dysfunction in diabetes. We subjected mice lacking TRPV1 [TRPV1(−/−)], db/ db, and control C57BLKS/J mice to in vivo infusion of the TRPV1 agonist capsaicin or the α-adrenergic agonist phenylephrine (PE) to examine the integrated circulatory actions of TRPV1. Capsaicin (1, 10, 20, and 100 μg/kg) dose dependently increased MAP in control mice (5.7 ± 1.6, 11.7 ± 2.1, 25.4 ± 3.4, and 51.6 ± 3.9%), which was attenuated in db/db mice (3.4 ± 2.1, 3.9 ± 2.1, 7.0 ± 3.3, and 17.9 ± 6.2%). TRPV1(−/−) mice exhibited no changes in MAP in response to capsaicin, suggesting the actions of this agonist are specific to TRPV1 activation. Immunoblot analysis revealed decreased aortic TRPV1 protein expression in db/db compared with control mice. Capsaicin-induced responses were recorded following inhibition of endothelin A and B receptors (ETA /ETB). Inhibition of ETA receptors abolished the capsaicin-mediated increases in MAP. Combined antagonism of ETA and ETB receptors did not further inhibit the capsaicin response. Cultured endothelial cell exposure to capsaicin increased endothelin production as shown by an endothelin ELISA assay, which was attenuated by inhibition of TRPV1 or endothelin-converting enzyme. TRPV1 channels contribute to the regulation of vascular reactivity and MAP via production of endothelin and subsequent activation of vascular ETA receptors. Impairment of TRPV1 channel function may contribute to vascular dysfunction in diabetes.
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Affiliation(s)
- Vahagn A. Ohanyan
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
| | - Giacinta Guarini
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
| | - Charles K. Thodeti
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
| | - Phani K. Talasila
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
| | - Priya Raman
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
| | - Rebecca M. Haney
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
| | - J. Gary Meszaros
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
| | - Derek S. Damron
- Department of Biological Sciences, Kent State University, Kent, Ohio
| | - Ian N. Bratz
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
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Wickley PJ, Yuge R, Russell MS, Zhang H, Sulak MA, Damron DS. Propofol modulates agonist-induced transient receptor potential vanilloid subtype-1 receptor desensitization via a protein kinase Cepsilon-dependent pathway in mouse dorsal root ganglion sensory neurons. Anesthesiology 2010; 113:833-44. [PMID: 20808213 DOI: 10.1097/aln.0b013e3181eaa9a0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND The activity of transient receptor potential vanilloid subtype-1 (TRPV1) receptors, key nociceptive transducers in dorsal root ganglion sensory neurons, is enhanced by protein kinase C epsilon (PKCepsilon) activation. The intravenous anesthetic propofol has been shown to activate PKCepsilon. Our objectives were to examine whether propofol modulates TRPV1 function in dorsal root ganglion neurons via activation of PKCepsilon. METHODS Lumbar dorsal root ganglion neurons from wild-type and PKC& epsilon;-null mice were isolated and cultured for 24 h. Intracellular free Ca concentration was measured in neurons by using fura-2 acetoxymethyl ester. The duration of pain-associated behaviors was also assessed. Phosphorylation of PKCepsilon and TRPV1 and the cellular translocation of PKCepsilon from cytosol to membrane compartments were assessed by immunoblot analysis. RESULTS In wild-type neurons, repeated stimulation with capsaicin (100 nm) progressively decreased the transient rise in intracellular free Ca concentration. After desensitization, exposure to propofol rescued the Ca response. The resensitizing effect of propofol was absent in neurons obtained from PKCepsilon-null mice. Moreover, the capsaicin-induced desensitization of TRPV1 was markedly attenuated in the presence of propofol in neurons from wild-type mice but not in neurons from PKCepsilon-null mice. Propofol also prolonged the duration of agonist-induced pain associated behaviors in wild-type mice. In addition, propofol increased phosphorylation of PKCepsilon as well as TRPV1 and stimulated translocation of PKCepsilon from cytosolic to membrane fraction. DISCUSSION Our results indicate that propofol modulates TRPV1 sensitivity to capsaicin and that this most likely occurs through a PKCepsilon-mediated phosphorylation of TRPV1.
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Affiliation(s)
- Peter J Wickley
- Department of Biological Sciences, Kent State University, Kent, Ohio, USA
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Mukherjee R, Donnay EG, Radomski MA, Miller C, Redfern DA, Gericke A, Damron DS, Brasch NE. Vanadium–vitamin B12 bioconjugates as potential therapeutics for treating diabetes. Chem Commun (Camb) 2008:3783-5. [DOI: 10.1039/b806598e] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Jane-wit D, Altuntas CZ, Johnson JM, Yong S, Wickley PJ, Clark P, Wang Q, Popović ZB, Penn MS, Damron DS, Perez DM, Tuohy VK. β
1
-Adrenergic Receptor Autoantibodies Mediate Dilated Cardiomyopathy by Agonistically Inducing Cardiomyocyte Apoptosis. Circulation 2007; 116:399-410. [PMID: 17620508 DOI: 10.1161/circulationaha.106.683193] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Background—
Antibodies to the β
1
-adrenergic receptor (β
1
AR) are detected in a substantial number of patients with idiopathic dilated cardiomyopathy (DCM). The mechanism whereby these autoantibodies exert their pathogenic effect is unknown. Here, we define a causal mechanism whereby β
1
AR-specific autoantibodies mediate noninflammatory cardiomyocyte cell death during murine DCM.
Methods and Results—
We used the β
1
AR protein as an immunogen in SWXJ mice and generated a polyclonal battery of autoantibodies that showed selective binding to the β
1
AR. After transfer into naive male hosts, β
1
AR antibodies elicited fulminant DCM at high frequency. DCM was attenuated after immunoadsorption of β
1
AR IgG before transfer and by selective pharmacological antagonism of host β
1
AR but not β
2
AR. We found that β
1
AR autoantibodies shifted the β
1
AR into the agonist-coupled high-affinity state and activated the canonical cAMP-dependent protein kinase A signaling pathway in cardiomyocytes. These events led to functional alterations in intracellular calcium handling and contractile function. Sustained agonism by β
1
AR autoantibodies elicited caspase-3 activation, cardiomyocyte apoptosis, and DCM in vivo, and these processes were prevented by in vivo treatment with the pan-caspase inhibitor Z-VAD-FMK.
Conclusions—
Our data show how β
1
AR-specific autoantibodies elicit DCM by agonistically inducing cardiomyocyte apoptosis.
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Affiliation(s)
- Daniel Jane-wit
- Department of Immunology, NB30, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA
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Abstract
Background
The authors' objective was to identify the role of the Na+-Ca2+ exchanger (NCX) in mediating the contractile dysfunction observed in diabetic cardiomyocytes before and after exposure to propofol.
Methods
Freshly isolated ventricular myocytes were obtained from normal and diabetic rat hearts. Intracellular concentration of Ca2+ and cell shortening were simultaneously measured in electrically stimulated, ventricular myocytes using fura-2 and video-edge detection, respectively. Postrest potentiation (PRP) and sarcoplasmic reticulum Ca2+ load were used to assess propofol-induced changes in the activity of the NCX.
Results
Propofol (10 microM) increased PRP in diabetic cardiomyocytes but had no effect on PRP in normal cardiomyocytes. Removal of sodium enhanced and KB-R7943 (reverse mode NCX inhibitor) blocked PRP in both normal and diabetic cardiomyocytes. In the absence of sodium, propofol enhanced PRP in diabetic cardiomyocytes but had no additional effect in normal cardiomyocytes. KB-R7943 completely blocked propofol-induced potentiation of peak intracellular concentration of Ca2+ and shortening in both cell types. Propofol increased sarcoplasmic reticulum Ca2+ load and prolonged removal of cytosolic Ca2+ in diabetic cardiomyocytes, but not in normal cardiomyocytes. Removal of sodium enhanced propofol-induced increases in sarcoplasmic reticulum Ca2+ load and further prolonged removal of cytosolic Ca2+, whereas KB-R7943 completely blocked propofol-induced increase in sarcoplasmic reticulum Ca2+ load. Protein kinase C inhibition with bisindolylmaleimide I prevented the propofol-induced increase in PRP and prolongation in Ca2+ removal.
Conclusions
These data suggest that propofol enhances PRP via activation of reverse mode NCX, but attenuates Ca2+ removal from the cytosol via inhibition of forward mode NCX in diabetic cardiomyocytes. The actions of propofol are mediated via a protein kinase C-dependent pathway.
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Affiliation(s)
- Peter J Wickley
- Center for Anesthesiology Research, Division of Anesthesiology, Critical Care Medicine, Cleveland, Ohio 44195, USA
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Abstract
BACKGROUND Myocardial protection by anesthetics is known to involve activation of protein kinase C (PKC). The authors' objective was to identify the PKC isoforms activated by propofol in rat ventricular myocytes. They also assessed the intracellular location of individual PKC isoforms before and after treatment with propofol. METHODS Freshly isolated ventricular myocytes were obtained from adult rat hearts. Immunoblot analysis of cardiomyocyte subcellular fractions was used to assess translocation of individual PKC isoforms before and after exposure to propofol. An enzyme-linked immunosorbent assay kit was used for measuring PKC activity. Immunocytochemistry and confocal microscopy were used to visualize the intracellular location of the individual PKC isoforms. RESULTS Under baseline conditions, PKC-alpha, PKC-delta, and PKC-zeta were associated with both the cytosolic and membrane fractions, whereas PKC-epsilon was exclusively located in the cytosolic fraction. Propofol (10 microM) caused translocation of PKC-alpha, PKC-delta, PKC-epsilon, and PKC-zeta from cytosolic to membrane fraction and increased total PKC activity (211 +/- 17% of baseline; P = 0.003) in a dose-dependent manner. Immunocytochemical localization of the individual PKC isoforms demonstrated that propofol caused translocation of PKC-alpha to the intercalated discs and z-lines; PKC-delta to the perinuclear region; PKC-epsilon to sites associated with the z-lines, intercalated discs, and the sarcolemma; and PKC-zeta to the nucleus. CONCLUSIONS These results demonstrate that propofol causes an increase in PKC activity in rat ventricular myocytes. Propofol stimulates translocation of PKC-alpha, PKC-delta, PKC-epsilon, and PKC-zeta to distinct intracellular sites in cardiomyocytes. This may be a fundamentally important cellular mechanism of anesthesia-induced myocardial protection in the setting of ischemia-reperfusion injury.
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Wickley PJ, Shiga T, Murray PA, Damron DS. Propofol decreases myofilament Ca2+ sensitivity via a protein kinase C-, nitric oxide synthase-dependent pathway in diabetic cardiomyocytes. Anesthesiology 2006; 104:978-87. [PMID: 16645450 DOI: 10.1097/00000542-200605000-00014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The authors' objective was to assess the role of protein kinase C (PKC) and nitric oxide synthase (NOS) in mediating the effects of propofol on diabetic cardiomyocyte contractility, intracellular free Ca2+ concentration ([Ca2+]i), and myofilament Ca2+ sensitivity. METHODS Freshly isolated ventricular myocytes were obtained from normal and diabetic rat hearts. [Ca2+]i and cell shortening were simultaneously measured in electrically stimulated, ventricular myocytes using fura-2 and video-edge detection, respectively. Actomyosin adenosine triphosphatase activity and troponin I (TnI) phosphorylation were assessed in [32P]orthophosphate-labeled myofibrils. Western blot analysis was used to assess expression of PKC and NOS. RESULTS Propofol (10 microM) decreased peak shortening by 47 +/- 6% with little effect on peak [Ca2+]i (92 +/- 5% of control) in diabetic myocytes. Maximal actomyosin adenosine triphosphatase activity was reduced by 43 +/- 7% and TnI phosphorylation was greater (32 +/- 6%) in diabetic myofibrils compared with normal. Propofol reduced actomyosin adenosine triphosphatase activity by 17 +/- 7% and increased TnI phosphorylation in diabetic myofibrils. PKC inhibition prevented the propofol-induced increase in TnI phosphorylation and decrease in shortening. Expression of PKC-alpha, PKC-delta, PKC-epsilon, and constitutive NOS were up-regulated and inducible NOS was expressed in diabetic cardiomyocytes. NOS inhibition attenuated the propofol-induced decrease in shortening. CONCLUSION Myofilament Ca2+ sensitivity and, to a lesser extent, peak [Ca2+]i are decreased in diabetic cardiomyocytes. Increases in PKC and NOS expression in combination with TnI phosphorylation seem to contribute to the decrease in [Ca2+]i and myofilament Ca2+ sensitivity. Propofol decreases [Ca2+]i and shortening via a PKC-, NOS-dependent pathway.
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Kanaya N, Murray PA, Damron DS. Effects of L-type Ca2+ channel modulation on direct myocardial effects of diazepam and midazolam in adult rat ventricular myocytes. J Anesth 2006; 20:17-25. [PMID: 16421671 DOI: 10.1007/s00540-005-0356-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Accepted: 08/31/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE Our objective was to determine whether an L-type Ca2+ channel modulation could alter myocardial depression induced by midazolam or diazepam in adult rat ventricular myocytes. METHODS Freshly isolated rat ventricular myocytes were loaded with fura-2/AM and field-stimulated (0.3 Hz) at 28 degrees C. Amplitude and timing of intracellular Ca2+ concentration ([Ca2+]i) and myocyte shortening were simultaneously monitored in individual cells. RESULTS Midazolam (3-100 microM) caused a decrease in both peak [Ca2+]i and shortening. Diazepam (30, 100 microM) increased myocyte shortening and peak [Ca2+]i; however, higher concentration of diazepam (300 microM) decreased shortening and peak [Ca2+]i. Bay K 8644 (0.01-10 microM), an L-type Ca2+ channel agonist, caused dose-dependent increases in peak [Ca2+]i and shortening. In contrast, verapamil (0.1-50 microM), an L-type Ca(2+) channel antagonist, caused dose-dependent decreases in peak [Ca2+]i and shortening. Dose-response curves to benzodiazepines on peak [Ca2+]i and shortening were not affected by pretreatment with Bay K 8644 (0.1 microM) or verapamil (1 microM). Diazepam (30, 100 microM), but not midazolam (3-30 microM), increased shortening and [Ca2+]i in the presence or absence of L-type Ca2+ channel modulators. Diazepam (30 microM) and midazolam (10 microM) had no effect on peak [Ca2+]i of a caffeine-induced [Ca2+]i transient, which was used as a measure of SR Ca2+ content. CONCLUSION Midazolam and diazepam have differential effects on cardiac E-C coupling. Diazepam, but not midazolam, enhances cardiac E-C coupling independent of L-type Ca2+ channel modulation.
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Affiliation(s)
- Noriaki Kanaya
- Department of Anesthesiology, Sapporo Medical University School of Medicine, S-1, W-16, Chuo-ku, Sapporo 060-8643, Japan
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Abstract
Background
The rationale for this study is that the depressant effect of propofol on cardiac function in vitro is highly variable but may be explained by differences in the temperature and stimulation frequency used for the study. Both temperature and stimulation frequency are known to modulate cellular mechanisms that regulate intracellular free Ca2+ concentration ([Ca2+]i) and myofilament Ca2+ sensitivity in cardiac muscle. The authors hypothesized that temperature and stimulation frequency play a major role in determining propofol-induced alterations in [Ca2+]i and contraction in individual, electrically stimulated cardiomyocytes and the function of isolated perfused hearts.
Methods
Freshly isolated myocytes were obtained from adult rat hearts, loaded with fura-2, and placed on the stage of an inverted fluorescence microscope in a temperature-regulated bath. [Ca2+]i and myocyte shortening were simultaneously measured in individual cells at 28 degrees or 37 degrees C at various stimulation frequencies (0.3, 0.5, 1, 2, and 3 Hz) with and without propofol. Langendorff perfused hearts paced at 180 or 330 beats/min were used to assess the effects of propofol on overall cardiac function.
Results
At 28 degrees C (hypothermic) and, to a lesser extent, at 37 degrees C (normothermic), increasing stimulation frequency increased peak shortening and [Ca2+]i. Times to peak shortening and rate of relengthening were more prolonged at 28 degrees C compared with 37 degrees C at low stimulation frequencies (0.3 Hz), whereas the same conditions for [Ca2+]i were not altered by temperature. At 0.3 Hz and 28 degrees C, propofol caused a dose-dependent decrease in peak shortening and peak [Ca2+]i. These changes were greater at 28 degrees C compared with 37 degrees C and involved activation of protein kinase C. At a frequency of 2 Hz, there was a rightward shift in the dose-response relation for propofol on [Ca2+]i and shortening at both 37 degrees and 28 degrees C compared with that observed at 0.3 Hz. In Langendorff perfused hearts paced at 330 beats/min, clinically relevant concentrations of propofol decreased left ventricular developed pressure, with the effect being less at 28 degrees C compared with 37 degrees C. In contrast, only a supraclinical concentration of propofol decreased left ventricular developed pressure at 28 degrees C at either stimulation frequency.
Conclusion
These results demonstrate that temperature and stimulation frequency alter the inhibitory effect of propofol on cardiomyocyte [Ca2+]i and contraction. In isolated cardiomyocytes, the inhibitory effects of propofol are more pronounced during hypothermia and at higher stimulation frequencies and involve activation of protein kinase C. In Langendorff perfused hearts at constant heart rate, the inhibitory effects of propofol at clinically relevant concentrations are more pronounced during normothermic conditions.
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Affiliation(s)
- Noriaki Kanaya
- Division of Anesthesiology, The Cleveland Clinic Foundation, Ohio 44195, USA
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Abstract
Background
The objective of this study was to identify the extent to which propofol alters intracellular free Ca2+ concentration ([Ca2+]i), myofilament Ca sensitivity, and contraction of individual cardiomyocytes during activation of alpha1a adrenoreceptors and to determine the cellular mechanism of action.
Methods
Freshly isolated ventricular myocytes were obtained from adult rat hearts. Myocyte shortening and [Ca2+]i were simultaneously monitored in individual cardiomyocytes exposed to phenylephrine after treatment with chloroethylclonidine (alpha1b-adrenoreceptor antagonist) and BMY 7378 (alpha1d-adrenoreceptor antagonist). Data are reported as mean +/- SD.
Results
Phenylephrine increased myocyte shortening by 124 +/- 9% (P = 0.002), whereas peak [Ca2+]i only increased by 8 +/- 3% (P = 0.110). Inhibition of phospholipase A2 and phospholipase C attenuated the phenylephrine-induced increase in shortening by 84 +/- 11% (P = 0.004) and 15 +/- 6% (P = 0.010), respectively. Inhibition of protein kinase C (PKC) and Rho kinase attenuated the phenylephrine-induced increase in shortening by 17 +/- 8% (P = 0.010) and 74 +/- 13% (P = 0.006), respectively. In the presence of phenylephrine, propofol increased shortening by 40 +/- 6% (P = 0.002), with no concomitant increase in [Ca2+]i. PKC inhibition prevented the propofol-induced increase in shortening. Selective inhibition of PKCalpha, PKCdelta, PKCepsilon, and PKCzeta reduced the propofol-induced increase in shortening by 12 +/- 5% (P = 0.011), 36 +/- 8% (P = 0.001), 32 +/- 9% (P = 0.007), and 19 +/- 5% (P = 0.008), respectively. Na+ - H+ exchange inhibition reduced the propofol-induced increase in shortening by 56 +/- 7% (P = 0.001).
Conclusion
Activation of alpha1a adrenoreceptors increases cardiomyocyte shortening primarily via a phospholipase A2-dependent, Rho kinase-dependent increase in myofilament Ca2+ sensitivity. Propofol further increases myofilament Ca2+ sensitivity and shortening via a PKC-dependent pathway and an increase in Na+ - H+ exchange activity.
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Affiliation(s)
- Brad D Gable
- Center for Anesthesiology Research, Division of Anesthesiology and Critical care Medicine, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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Shiga T, Yong S, Carino J, Murray PA, Damron DS. Droperidol inhibits intracellular Ca2+, myofilament Ca2+ sensitivity, and contraction in rat ventricular myocytes. Anesthesiology 2005; 102:1165-73. [PMID: 15915029 DOI: 10.1097/00000542-200506000-00016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Droperidol has recently been associated with cardiac arrhythmias and sudden cardiac death. Changes in action potential duration seem to be the cause of the arrhythmic behavior, which can lead to alterations in intracellular free Ca concentration ([Ca]i). Because [Ca]i and myofilament Ca sensitivity are key regulators of myocardial contractility, the authors' objective was to identify whether droperidol alters [Ca]i or myofilament Ca sensitivity in rat ventricular myocytes and to identify the cellular mechanisms responsible for these effects. METHODS Freshly isolated rat ventricular myocytes were obtained from adult rat hearts. Myocyte shortening, [Ca]i, nitric oxide production, intracellular pH, and action potentials were monitored in cardiomyocytes exposed to droperidol. Langendorff perfused hearts were used to assess overall cardiac function. RESULTS Droperidol (0.03-1 mum) caused concentration-dependent decreases in peak [Ca]i and shortening. Droperidol inhibited 35 mm KCl-induced increase in [Ca]i, with little direct effect on sarcoplasmic reticulum Ca stores. Droperidol had no effect on action potential duration but caused a rightward shift in the concentration-response curve to extracellular Ca for shortening, with no concomitant effect on peak [Ca]i. Droperidol decreased pHi and increased nitric oxide production. Droperidol exerted a negative inotropic effect in Langendorff perfused hearts. CONCLUSION These data demonstrate that droperidol decreases cardiomyocyte function, which is mediated by a decrease in [Ca]i and a decrease in myofilament Ca sensitivity. The decrease in [Ca]i is mediated by decreased sarcolemmal Ca influx. The decrease in myofilament Ca sensitivity is likely mediated by a decrease in pHi and an increase in nitric oxide production.
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Affiliation(s)
- Toshiya Shiga
- Center for Anesthesiology Research, Division of Anesthesiology and Critical Care Medicine, Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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Abstract
Background
The authors investigated the extent and cellular mechanisms by which the intravenous anesthetic ketamine alters acetylcholine-induced contraction in pulmonary veins (PVs). They tested the hypothesis that ketamine inhibits acetylcholine contraction in PVs.
Methods
Canine PV rings with endothelium (E+) and without endothelium (E-) were isolated for measurement of isometric tension. The effects of ketamine (10(-5) m approximately 10(-3) m) on acetylcholine contraction were assessed in E+ and E- rings. The effects of inhibiting nitric oxide synthase on ketamine-induced changes in acetylcholine contraction were investigated in E+ rings, whereas the effects of Ca2+ influx and Ca2+ release were investigated in E- rings. In fura-2 loaded E- PV strips, the effects of ketamine (10(-4) m) on the intracellular Ca2+ concentration-tension relation (i.e., myofilament Ca sensitivity) were assessed in the presence or absence of acetylcholine. The roles of the protein kinase C and rho-kinase signaling pathways in ketamine-induced changes in myofilament Ca2+ sensitivity were also investigated.
Results
Ketamine caused dose-dependent (P < 0.001) inhibition of acetylcholine contraction in E+ and E- PV rings. The ketamine-induced attenuation of acetylcholine contraction was still observed after inhibition of nitric oxide synthase (P = 0.002), Ca2+ influx (P < 0.001), and Ca2+ release (P = 0.021). Ketamine alone had no effect on myofilament Ca2+ sensitivity (P = 0.892) but attenuated (P = 0.038) the acetylcholine-induced increase in myofilament Ca2+ sensitivity. This attenuation was still observed after rho-kinase inhibition (P = 0.039), whereas it was abolished by protein kinase C inhibition (P = 0.798).
Conclusions
Ketamine attenuates acetylcholine contraction by inhibiting the acetylcholine-induced increase in myofilament Ca2+ sensitivity, which is mediated by the protein kinase C signaling pathway.
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Affiliation(s)
- Xueqin Ding
- Center for Anesthesiology Research, The Cleveland Clinic Foundation, The Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Ohio 44195, USA
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Abstract
We investigated the role of Akt-1, one of the major downstream effectors of phosphoinositide 3-kinase (PI3K), in platelet function using mice in which the gene for Akt-1 had been inactivated. Using ex vivo techniques, we showed that Akt-1-deficient mice exhibited impaired platelet aggregation and spreading in response to various agonists. These differences were most apparent in platelets activated with low concentrations of thrombin. Although Akt-1 is not the predominant Akt isoform in mouse platelets, its absence diminished the amount of total phospho-Akt and inhibited increases in intracellular Ca(2+) concentration in response to thrombin. Moreover, thrombin-induced platelet alpha-granule release as well as release of adenosine triphosphate from dense granules was also defective in Akt-1-null platelets. Although the absence of Akt-1 did not influence expression of the major platelet receptors for thrombin and collagen, fibrinogen binding in response to these agonists was significantly reduced. As a consequence of impaired alpha(IIb)beta(3) activation and platelet aggregation, Akt-1 null mice showed significantly longer bleeding times than wild-type mice.
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Affiliation(s)
- Juhua Chen
- Joseph J. Jacobs Center for Thrombosis and Vascular Biology, Department of Molecular Cardiology, Joseph J. Jacobs Center for Thrombosis and Vascular Biology, Cleveland Clinic Foundation, NB50, 9500 Euclid Ave, Cleveland, OH 44195, USA
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Ruehr ML, Russell MA, Ferguson DG, Bhat M, Ma J, Damron DS, Scott JD, Bond M. Targeting of protein kinase A by muscle A kinase-anchoring protein (mAKAP) regulates phosphorylation and function of the skeletal muscle ryanodine receptor. J Biol Chem 2003; 278:24831-6. [PMID: 12709444 DOI: 10.1074/jbc.m213279200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein kinase A anchoring proteins (AKAPs) tether cAMP-dependent protein kinase (PKA) to specific subcellular locations. The muscle AKAP, mAKAP, co-localizes with the sarcoplasmic reticulum Ca2+ release channel or ryanodine receptor (RyR). The purpose of this study was to determine whether anchoring of PKA by mAKAP regulates RyR function. Either mAKAP or mAKAP-P, which is unable to anchor PKA, was expressed in CHO cells stably expressing the skeletal muscle isoform of RyR (CHO-RyR1). Immunoelectron microscopy showed that mAKAP co-localized with RyR1 in disrupted skeletal muscle. Following the addition of 10 microm forskolin to activate adenylyl cyclase, RyR1 phosphorylation in CHO-RyR1 cells expressing mAKAP increased by 42.4 +/- 6.6% (n = 4) compared with cells expressing mAKAP-P. Forskolin treatment alone did not increase the amplitude of the cytosolic Ca2+ transient in CHO-RyR1 cells expressing mAKAP or mAKAP-P; however, forskolin plus 10 mm caffeine elicited a cytosolic Ca2+ transient, the amplitude of which increased by 22% (p < 0.05) in RyR1/mAKAP-expressing cells compared with RyR1/mAKAP-P-expressing cells. Therefore, localization of PKA by mAKAP at RyR1 increases both PKA-dependent RyR phosphorylation as well as efflux of Ca2+ through the RyR. Therefore, RyR1 function is regulated by mAKAP targeting of PKA, implying an important functional role for PKA phosphorylation of RyR in skeletal muscle.
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Affiliation(s)
- Mary L Ruehr
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland, Ohio 44195, USA
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Kanaya N, Gable B, Murray PA, Damron DS. Propofol increases phosphorylation of troponin I and myosin light chain 2 via protein kinase C activation in cardiomyocytes. Anesthesiology 2003; 98:1363-71. [PMID: 12766644 DOI: 10.1097/00000542-200306000-00010] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Troponin I (TnI) and myosin light chain 2 (MLC2) are important myofibrillar proteins involved in the regulation of myofilament calcium (Ca2+) sensitivity and cardiac inotropy. The objectives of this study were to determine the role of protein kinase C (PKC) in mediating propofol-induced changes in actomyosin adenosine triphosphatase activity in cardiac myofibrils and to examine the extent to which propofol alters the phosphorylation of TnI and MLC2 in cardiomyocytes. METHODS Freshly isolated adult rat ventricular myocytes were used for the study. Cardiac myofibrils were extracted for assessment of actomyosin adenosine triphosphatase activity and phosphorylation of TnI and MLC2. Western blot analysis for PKC-alpha was performed on cardiomyocyte subcellular fractions. Simultaneous measurement of intracellular free Ca2+ concentration ([Ca2+](i)) and myocyte shortening was assessed using fura-2 and video edge detection, respectively. RESULTS Propofol (30 microM) reduced the Ca2+ concentration required for activation of actomyosin adenosine triphosphatase activity, and this effect was abolished by bisindolylmaleimide I. In addition, propofol stimulated dose-dependent phosphorylation of TnI and MLC2. PKC activation with phorbol myristic acetate also stimulated an increase in phosphorylation of TnI and MLC2. The actions of propofol and phorbol myristic acetate together on phosphorylation of TnI and MLC2 were not additive. PKC inhibition with bisindolylmaleimide I attenuated phorbol myristic acetate- and propofol-induced phosphorylation of TnI and MLC2. Propofol stimulated translocation of PKC-alpha from cytosolic to membrane fraction. Propofol caused a shift in the extracellular Ca2+-shortening relationship, and this effect was abolished by bisindolylmaleimide I. CONCLUSIONS These results suggest that propofol increases myofilament Ca2+ sensitivity via a PKC-dependent pathway involving the phosphorylation of MLC2.
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Affiliation(s)
- Noriaki Kanaya
- Center for Anesthesiology Research, Division of Anesthesiology and Critical Care Medicine, Cleveland Clinic Foundation, Ohio 44195, USA
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Chaudhuri P, Colles SM, Damron DS, Graham LM. Lysophosphatidylcholine inhibits endothelial cell migration by increasing intracellular calcium and activating calpain. Arterioscler Thromb Vasc Biol 2003; 23:218-23. [PMID: 12588762 DOI: 10.1161/01.atv.0000052673.77316.01] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Endothelial cell (EC) migration, essential for reestablishing arterial integrity after vascular injury, is inhibited by oxidized LDL (oxLDL) and lysophosphatidylcholine (lysoPC) that are present in the arterial wall. We tested the hypothesis that a mechanism responsible for lysoPC-induced inhibition is increased intracellular free calcium concentration ([Ca(2+)](i)). METHODS AND RESULTS LysoPC, at concentrations that inhibit in vitro EC migration to 35% of control, increased [Ca(2+)](i) levels 3-fold. These effects of lysoPC were concentration dependent and reversible. LysoPC induced Ca(2+) influx within 10 minutes, and [Ca(2+)](i) remained elevated for 2 hours. The calcium ionophore A23187 also increased [Ca(2+)](i) and inhibited EC migration. Chelators of intracellular Ca(2+) (BAPTA/AM and EGTA/AM) and nonvoltage-sensitive channel blockers (lanthanum chloride and gadolinium chloride) blunted the lysoPC-induced [Ca(2+)](i) rise and partially preserved EC migration. After lysoPC treatment, calpain, a calcium-dependent cysteine protease, was activated, and cytoskeletal changes occurred. Calpain inhibitors (calpastatin, MDL28170, and calpeptin) added before lysoPC prevented cytoskeletal protein cleavage and preserved EC migration at 60% of control levels. CONCLUSIONS LysoPC increases [Ca(2+)](i). In turn, activating calpains that can alter the cytoskeleton are activated and EC migration is inhibited.
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Affiliation(s)
- Pinaki Chaudhuri
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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Tanaka S, Kanaya N, Homma Y, Damron DS, Murray PA. Propofol increases pulmonary artery smooth muscle myofilament calcium sensitivity: role of protein kinase C. Anesthesiology 2002; 97:1557-66. [PMID: 12459685 DOI: 10.1097/00000542-200212000-00031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Vascular smooth muscle tone is regulated by changes in intracellular free Ca2+ concentration ([Ca2+]i) and myofilament Ca2+ sensitivity. These cellular mechanisms could serve as targets for anesthetic agents that alter vasomotor tone. This study tested the hypothesis that propofol increases myofilament Ca2+ sensitivity in pulmonary artery smooth muscle (PASM) via the protein kinase C (PKC) signaling pathway. METHODS Canine PASM strips were denuded of endothelium, loaded with fura-2/AM, and suspended in modified Krebs-Ringer's buffer at 37 degrees C for simultaneous measurement of isometric tension and [Ca2+]i. RESULTS The KCl (30 mm) induced monotonic increases in [Ca2+]i and tension. Verapamil, an L-type Ca2+ channel blocker, attenuated KCl-induced increases in [Ca2+]i and tension to an equal extent. In contrast, propofol attenuated KCl-induced increases in [Ca2+]i to a greater extent than concomitant changes in tension and caused an upward shift in the peak tension-[Ca2+]i relation. Increasing extracellular Ca2+ in the presence of 30 mM KCl resulted in similar increases in [Ca2+]i in control and propofol-pretreated strips, whereas concomitant increases in tension were greater during propofol administration. The Ca2+ ionophore, ionomycin (0.1 microm), increased [Ca2+]i to approximately 50% of the value induced by 60 mm KCl. Under these conditions, propofol (10, 100 microm) caused increases in tension equivalent to 11 +/- 2 and 28 +/- 3% of the increases in tension in response to 60 mM KCl, whereas [Ca2+]i was slightly decreased. Similar effects were observed in response to the PKC activator, phorbol 12-myristate 13-acetate (PMA, 1 microm). Specific inhibition of PKC with bisindolylmaleimide I before ionomycin administration decreased the propofol- and PMA-induced increases in tension and abolished the propofol- and PMA-induced decreases in [Ca2+]i. Selective inhibition of Ca2+ -dependent PKC isoforms with Gö 6976 also attenuated propofol-induced increases in tension. CONCLUSION These results suggest that propofol increases myofilament Ca2+ sensitivity in PASM, and this effect involves the PKC signaling pathway.
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Affiliation(s)
- Satoru Tanaka
- Center for Anesthesiology Research FF40, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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Kanaya N, Murray PA, Damron DS. The differential effects of midazolam and diazepam on intracellular Ca2+ transients and contraction in adult rat ventricular myocytes. Anesth Analg 2002; 95:1637-44, table of contents. [PMID: 12456430 DOI: 10.1097/00000539-200212000-00030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
UNLABELLED We investigated the direct effects of midazolam and diazepam on cardiac excitation-contraction coupling in adult rat ventricular myocytes. Freshly isolated rat ventricular myocytes were loaded with fura-2/AM and field-stimulated at 28 degrees C. Intracellular Ca(2+) transients (340:380 ratio) and myocyte shortening (video edge detection) were simultaneously monitored in individual cells. Midazolam (3-100 micro M) caused a dose-dependent decrease in both peak intracellular Ca(2+) and cell shortening. Diazepam (30 and 100 micro M) increased myocyte shortening and peak Ca(2+) concomitant with a decrease in time to peak Ca(2+). A larger concentration of diazepam (>300 micro M) nearly abolished intracellular Ca(2+) and cell shortening. Midazolam (100 micro M) and diazepam (300 micro M) decreased the amount of Ca(2+) released from intracellular stores in response to caffeine. Diazepam (30 micro M), but not midazolam (10 micro M), caused a downward shift in the dose-response curve to extracellular Ca(2+) for shortening, with no concomitant effect on peak intracellular Ca(2+) transient. These results indicate that midazolam and diazepam have different inotropic effects on cardiac excitation-contraction coupling at the cellular level, which is mediated by altering the availability of intracellular-free Ca(2+). However, the benzodiazepines have no direct influence on excitation-contraction coupling in rat ventricular myocytes, except at very large doses. Inhibition of Ca(2+) release from caffeine-sensitive intracellular Ca(2+) stores may play some part in myocardial depression at the larger concentrations of benzodiazepines. Diazepam, but not midazolam, decreased myofilament responsiveness to Ca(2+). IMPLICATIONS Midazolam and diazepam differentially alter the cardiac excitation-contraction coupling at the cellular level, which is mediated by altering the availability of intracellular free Ca(2+) in adult rat ventricular myocytes. In addition, diazepam, but not midazolam, decreases myofilament Ca(2+) sensitivity. However, the benzodiazepines have no direct influence on excitation-contraction coupling, except at very large doses.
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Affiliation(s)
- Noriaki Kanaya
- Center for Anesthesiology Research, The Cleveland Clinic Foundation, Ohio, USA.
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Damron DS, Kanaya N, Homma Y, Kim SO, Murray PA. Role of PKC, tyrosine kinases, and Rho kinase in alpha-adrenoreceptor-mediated PASM contraction. Am J Physiol Lung Cell Mol Physiol 2002; 283:L1051-64. [PMID: 12376358 DOI: 10.1152/ajplung.00345.2001] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Our objectives were to identify the relative contributions of intracellular free Ca2+ concentration ([Ca2+]i) and myofilament Ca2+ sensitivity in the pulmonary artery smooth muscle (PASM) contractile response to the alpha-adrenoreceptor agonist phenylephrine (PE) and to assess the role of PKC, tyrosine kinases (TK), and Rho kinase (ROK) in that response. Our hypothesis was that multiple signaling pathways are involved in the regulation of [Ca2+]i, myofilament Ca2+ sensitization, and vasomotor tone in response to alpha-adrenoreceptor stimulation of PASM. Simultaneous measurement of [Ca2+]i and isometric tension was performed in isolated canine pulmonary arterial strips loaded with fura 2-AM. PE-induced tension development was due to sarcolemmal Ca2+ influx, Ca2+ release from inositol 1,4,5-trisphosphate-dependent sarcoplasmic reticulum Ca2+ stores, and myofilament Ca2+ sensitization. Inhibition of either PKC or TK partially attenuated the sarcolemmal Ca2+ influx component and the myofilament Ca2+ sensitizing effect of PE. Combined inhibition of PKC and TK did not have an additive attenuating effect on PE-induced Ca2+ sensitization. ROK inhibition slightly decreased [Ca2+]i but completely inhibited myofilament Ca2+ sensitization. These results indicate that PKC and TK activation positively regulate sarcolemmal Ca2+ influx in response to alpha-adrenoreceptor stimulation in PASM but have relatively minor effects on myofilament Ca2+ sensitivity. ROK is the predominant pathway mediating PE-induced myofilament Ca2+ sensitization.
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Affiliation(s)
- Derek S Damron
- Center for Anesthesiology Research, Division of Anesthesiology and Critical Care Medicine, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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Kang SK, Kim DK, Damron DS, Baek KJ, Im MJ. Modulation of intracellular Ca(2+) via alpha(1B)-adrenoreceptor signaling molecules, G alpha(h) (transglutaminase II) and phospholipase C-delta 1. Biochem Biophys Res Commun 2002; 293:383-90. [PMID: 12054611 DOI: 10.1016/s0006-291x(02)00197-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We characterized the alpha(1B)-adrenoreceptor (alpha(1B)-AR)-mediated intracellular Ca(2+) signaling involving G alpha(h) (transglutaminase II, TGII) and phospholipase C (PLC)-delta 1 using DDT1-MF2 cell. Expression of wild-type TGII and a TGII mutant lacking transglutaminase activity resulted in significant increases in a rapid peak and a sustained level of intracellular Ca(2+) concentration ([Ca(2+)](i)) in response to activation of the alpha(1B)-AR. Expression of a TGII mutant lacking the interaction with the receptor or PLC-delta 1 substantially reduced both the peak and sustained levels of [Ca(2+)](i). Expression of TGII mutants lacking the interaction with PLC-delta 1 resulted in a reduced capacitative Ca(2+) entry. Reduced expression of PLC-delta 1 displayed a transient elevation of [Ca(2+)](i) and a reduction in capacitative Ca(2+) entry. Expression of the C2-domain of PLC-delta 1, which contains the TGII interaction site, resulted in reduction of the alpha(1B)-AR-evoked peak increase in [Ca(2+)](i), while the sustained elevation in [Ca(2+)](i) and capacitative Ca(2+) entry remained unchanged. These findings demonstrate that stimulation of PLC-delta 1 via coupling of the alpha(1B)-AR with TGII evokes both Ca(2+) release and capacitative Ca(2+) entry and that capacitative Ca(2+) entry is mediated by the interaction of TGII with PLC-delta 1.
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Affiliation(s)
- Sung Koo Kang
- Department of Molecular Cardiology, The Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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Kurokawa H, Murray PA, Damron DS. Propofol attenuates beta-adrenoreceptor-mediated signal transduction via a protein kinase C-dependent pathway in cardiomyocytes. Anesthesiology 2002; 96:688-98. [PMID: 11873046 DOI: 10.1097/00000542-200203000-00027] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Activation of beta adrenoreceptors by catecholamines is an important mechanism for increasing the inotropic state of the heart. The objectives of the current study were to investigate the effects of propofol on beta-adrenoreceptor-mediated increases in cardiomyocyte intracellular Ca2+ concentration ([Ca2+]i), cell shortening, L-type Ca2+ current (ICa) and cyclic adenosine monophosphate (cAMP) accumulation. The authors also investigated the site of action of propofol in the beta-adrenoreceptor signaling pathway, as well as the role of protein kinase C (PKC), and tested the hypothesis that propofol would inhibit the beta-adrenoreceptor signaling pathway via a PKC-dependent mechanism. METHODS Freshly isolated ventricular myocytes were obtained from adult rat and guinea pig hearts. Myocyte shortening (video edge detection) and [Ca2+]i (fura-2, 340/380 ratio) were monitored simultaneously in individual cells. Conventional whole cell patch clamp analysis was used to measure the ICa in individual myocytes. cAMP production was assessed in suspensions of myocytes using an enzyme immunoassay kit. RESULTS Propofol (0.1-10 mum) had no effect on steady state [Ca2+]i, cell shortening, ICa, or cAMP production. In contrast, propofol caused dose-dependent decreases in isoproterenol-stimulated increases in [Ca2+]i, shortening, ICa, and cAMP. Forskolin-induced increases in [Ca2+]i, shortening, and cAMP production were not altered by propofol. PKC activation with phorbol myristate acetate attenuated isoproterenol-stimulated cAMP production. Inhibition of PKC with bisindolylmaleimide (broad range inhibitor) or Gö 6976 (inhibitor of Ca2+-dependent PKC isoforms) abolished propofol-induced inhibition of isoproterenol-stimulated increases in [Ca2+]i, shortening, and cAMP production. CONCLUSIONS Clinically relevant concentrations of propofol attenuate beta-adrenergic signal transduction in cardiac myocytes via inhibition of cAMP production. The inhibitory site of action of propofol is upstream of adenylyl cyclase and involves activation of PKC alpha.
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Affiliation(s)
- Hiromi Kurokawa
- Center for Anesthesiology Research, Division of Anesthesiology and Critical Care Medicine, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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Abstract
BACKGROUND Depletion of intracellular Ca2+ stores results in capacitative Ca2+ entry (CCE) in pulmonary artery smooth muscle cells (PASMCs). The authors aimed to investigate the effects of propofol on CCE and to assess the extent to which protein kinase C (PKC) and tyrosine kinases mediate propofol-induced changes in CCE. METHODS Pulmonary artery smooth muscle cells were cultured from explants of canine intrapulmonary artery. Fura 2-loaded PASMCs were placed in a dish (37 degrees C) on an inverted fluorescence microscope. Intracellular Ca2+ concentration was measured using fura 2 in PASMCs using a dual-wavelength spectrofluorometer. Thapsigargin (1 microM), a sarcoplasmic reticulum Ca2+-adenosine triphosphatase inhibitor, was used to deplete intracellular Ca2+ stores after removing extracellular Ca2+. CCE was activated when extracellular Ca2+ (2.2 mM) was restored. RESULTS Thapsigargin caused a transient increase in intracellular Ca2+ concentration (182+/-11%). Restoring extracellular calcium (to induce CCE) resulted in a peak (246+/-12% of baseline) and a sustained (187+/-7% of baseline) increase in intracellular Ca2+ concentration. Propofol (1, 10, 100 microM) attenuated CCE in a dose-dependent manner (peak: 85+/-3, 70+/-4, 62+/-4%; sustained: 94+/-5, 80+/-5, 72+/-5% of control respectively). Tyrosine kinase inhibition (tyrphostin 23) attenuated CCE (peak: 67+/-4%; sustained: 74+/-5% of control), but the propofol-induced decrease in CCE was still apparent after tyrosine kinases inhibition. PKC activation (phorbol 12-myristate 13-acetate) attenuated CCE (peak: 48+/-1%; sustained: 53+/-3% of control), whereas PKC inhibition (bisindolylmaleimide) potentiated CCE (peak: 132+/-11%; sustained: 120+/-4% of control). Moreover, PKC inhibition abolished the propofol-induced attenuation of CCE. CONCLUSION Tyrosine kinases activate and PKC inhibits CCE in PASMCs. Propofol attenuates CCE primarily via a PKC-dependent pathway. CCE should be considered a possible cellular target for anesthetic agents that alter vascular smooth muscle tone.
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Affiliation(s)
- M Horibe
- Center for Anesthesiology Research, Division of Anesthesiology and Critical Care Medicine, The Cleveland Clinic Foundation, Ohio 44195, USA
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Kanaya N, Murray PA, Damron DS. Propofol increases myofilament Ca2+ sensitivity and intracellular pH via activation of Na+-H+ exchange in rat ventricular myocytes. Anesthesiology 2001; 94:1096-104. [PMID: 11465603 DOI: 10.1097/00000542-200106000-00026] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The objectives were to determine the extent and mechanism of action by which propofol increases myofilament Ca2+ sensitivity and intracellular pH (pHi) in ventricular myocytes. METHODS Freshly isolated adult rat ventricular myocytes were used for the study. Cardiac myofibrils were extracted for assessment of myofibrillar actomyosin adenosine triphosphatase (ATPase) activity. Myocyte shortening (video edge detection) and pHi (2',7'-bis-(2-carboxyethyl)-5(6')-carboxyfluorescein, 500/440 ratio) were monitored simultaneously in individual cells field-stimulated (0.3 Hz) and superfused with HEPES-buffered solution (pH 7.4, 30 degrees C). RESULTS Propofol (100 microM) reduced the Ca2+ concentration required for activation of myofibrillar actomyosin ATPase from pCa 5.7 +/- 0.01 to 6.6 +/- 0.01. Increasing pHi (7.05 +/- 0.03 to 7.39 +/- 0.04) with NH4Cl increased myocyte shortening by 35 +/- 12%. Washout of NH4Cl decreased pHi to 6.82 +/- 0.03 and decreased myocyte shortening to 52 +/- 10% of control. Propofol caused a dose-dependent increase in pHi but reduced myocyte shortening. The propofol-induced increase in pHi was attenuated, whereas the decrease in myocyte shortening was enhanced after pretreatment with ethylisopropyl amiloride, a Na+-H+ exchange inhibitor, or bisindolylmaleimide I, a protein kinase C inhibitor. Propofol also attenuated the NH4Cl-induced intracellular acidosis, increased the rate of recovery from acidosis, and attenuated the associated decrease in myocyte shortening. Propofol caused a leftward shift in the extracellular Ca2+-shortening relation, and this effect was attenuated by ethylisopropyl amiloride. CONCLUSIONS These results suggest that propofol increases the sensitivity of myofibrillar actomyosin ATPase to Ca2+ (ie., increases myofilament Ca2+ sensitivity), at least in part by increasing pHi via protein kinase C-dependent activation of Na+-H+ exchange.
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Affiliation(s)
- N Kanaya
- Center for Anesthesiology Research, Division of Anesthesiology and Critical Care Medicine, The Cleveland Clinic Foundation, Ohio 44195, USA
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Abstract
Myocardial inflammation contributes to the development of dilated cardiomyopathy, as well as other cardiac diseases. We have previously shown decreased left ventricular function in mice with autoimmune myocarditis. To test the hypothesis that decreased function is mediated by changes in contractility and/or Ca2+ cycling, we isolated cardiac myocytes from mice with myocarditis and age-matched controls at two time points: day 18 (prior to cardiac dysfunction) and day 35 (during cardiac dysfunction). We measured cell shortening and the Ca2+ transient simultaneously at 28 degrees C and 0.3 Hz. We also quantified proteins which regulate contractility and [Ca2+](i), using Western blot analysis. Results showed no change in cell shortening or systolic Ca2+ on day 18, despite a significant reduction in diastolic Ca2+. By day 35, the decrease in diastolic Ca2+ was accompanied by significantly reduced cell shortening and a decrease in the systolic Ca2+ transient. Protein levels of the sarcoplasmic reticulum Ca2+ ATPase were unchanged at both time points, while phospholamban and the sodium/calcium exchanger were significantly reduced in myosin-immunized mice at both time points. Calsequestrin was unchanged at day 18, but was significantly reduced in the myosin-immunized mice on day 35. Results of this study suggest that decreased diastolic Ca2+, as well as protein levels of phospholamban and the sodium/calcium exchanger, may actually contribute to disease progression in autoimmune myocarditis, while changes in calsequestrin may be related to systolic dysfunction in this model.
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Affiliation(s)
- L B Stull
- Center for Anesthesiology Research, Cleveland Clinic Foundation, 9500 Euclid Ave. Cleveland, OH 44195, USA
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Abstract
Compartmentalization of cAMP-dependent protein kinase A (PKA) by A-kinase anchoring proteins (AKAPs) targets PKA to distinct subcellular locations in many cell types. However, the question of whether AKAP-mediated PKA anchoring in the heart regulates cardiac contractile function has not been addressed. We disrupted AKAP-mediated PKA anchoring in cardiac myocytes by introducing, via adenovirus-mediated gene transfer, Ht31, a peptide that binds the PKA regulatory subunit type II (RII) with high affinity. This peptide competes with endogenous AKAPs for RII binding. Ht31P (a proline-substituted derivative), which does not bind RII, was used as a negative control. We then investigated the effects of Ht31 expression on RII distribution, Ca(2+) cycling, cell shortening, and PKA-dependent substrate phosphorylation. By confocal microscopy, we showed redistribution of RII from the perinuclear region and from periodic transverse striations in Ht31P-expressing cells to a diffuse cytosolic localization in Ht31-expressing cells. In the presence of 10 nmol/L isoproterenol, Ht31-expressing myocytes displayed an increased rate and amplitude of cell shortening and relaxation compared with control cells (uninfected and Ht31P-expressing myocytes); with isoproterenol stimulation we observed decreased time to 90% decline in Ca(2+) but no significant difference between Ht31-expressing and control cells in the rate of Ca(2+) cycling or amplitude of the Ca(2+) transient. The increase in PKA-dependent phosphorylation of troponin I and myosin binding protein C on isoproterenol stimulation was significantly reduced in Ht31-expressing cells compared with controls. Our results demonstrate that, in response to beta-adrenergic stimulation, cardiomyocyte function and substrate phosphorylation by PKA is regulated by targeting of PKA by AKAPs.
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Affiliation(s)
- M A Fink
- Department of Molecular Cardiology, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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Doi S, Damron DS, Ogawa K, Tanaka S, Horibe M, Murray PA. K(+) channel inhibition, calcium signaling, and vasomotor tone in canine pulmonary artery smooth muscle. Am J Physiol Lung Cell Mol Physiol 2000; 279:L242-51. [PMID: 10926547 DOI: 10.1152/ajplung.2000.279.2.l242] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the role of K(+) channels in the regulation of baseline intracellular free Ca(2+) concentration ([Ca(2+)](i)), alpha-adrenoreceptor-mediated Ca(2+) signaling, and capacitative Ca(2+) entry in pulmonary artery smooth muscle cells (PASMCs). Inhibition of voltage-gated K(+) channels with 4-aminopyridine (4-AP) increased the membrane potential and the resting [Ca(2+)](i) but attenuated the amplitude and frequency of the [Ca(2+)](i) oscillations induced by the alpha-agonist phenylephrine (PE). Inhibition of Ca(2+)-activated K(+) channels (with charybdotoxin) and inhibition (with glibenclamide) or activation of ATP-sensitive K(+) channels (with lemakalim) had no effect on resting [Ca(2+)](i) or PE-induced [Ca(2+)](i) oscillations. Thapsigargin was used to deplete sarcoplasmic reticulum Ca(2+) stores in the absence of extracellular Ca(2+). Under these conditions, 4-AP attenuated the peak and sustained components of capacitative Ca(2+) entry, which was observed when extracellular Ca(2+) was restored. Capacitative Ca(2+) entry was unaffected by charybdotoxin, glibenclamide, or lemakalim. In isolated pulmonary arterial rings, 4-AP increased resting tension and caused a leftward shift in the KCl dose-response curve. In contrast, 4-AP decreased PE-induced contraction, causing a rightward shift in the PE dose-response curve. These results indicate that voltage-gated K(+) channel inhibition increases resting [Ca(2+)](i) and tone in PASMCs but attenuates the response to PE, likely via inhibition of capacitative Ca(2+) entry.
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Affiliation(s)
- S Doi
- Center for Anesthesiology Research, Division of Anesthesiology and Critical Care Medicine, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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Xu Y, Zhu K, Hong G, Wu W, Baudhuin LM, Xiao Y, Damron DS. Sphingosylphosphorylcholine is a ligand for ovarian cancer G-protein-coupled receptor 1. Nat Cell Biol 2000; 2:261-7. [PMID: 10806476 DOI: 10.1038/35010529] [Citation(s) in RCA: 237] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Sphingosylphosphorylcholine (SPC) is a bioactive lipid that acts as an intracellular and extracellular signalling molecule in numerous biological processes. Many of the cellular actions of SPC are believed to be mediated by the activation of unidentified G-protein-coupled receptors. Here we show that SPC is a high-affinity ligand for an orphan receptor, ovarian cancer G-protein-coupled receptor 1 (OGR1). In OGR1-transfected cells, SPC binds to OGR1 with high affinity (Kd = 33.3 nM) and high specificity and transiently increases intracellular calcium. The specific binding of SPC to OGR1 also activates p42/44 mitogen-activated protein kinases (MAP kinases) and inhibits cell proliferation. In addition, SPC causes internalization of OGR1 in a structurally specific manner.
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Affiliation(s)
- Y Xu
- Department of Cancer Biology, Cleveland Clinic Foundation, OH 44195, USA.
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Doi S, Damron DS, Horibe M, Murray PA. Capacitative Ca(2+) entry and tyrosine kinase activation in canine pulmonary arterial smooth muscle cells. Am J Physiol Lung Cell Mol Physiol 2000; 278:L118-30. [PMID: 10645899 DOI: 10.1152/ajplung.2000.278.1.l118] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the role of capacitative Ca(2+) entry and tyrosine kinase activation in mediating phenylephrine (PE)-induced oscillations in intracellular free Ca(2+) concentration ([Ca(2+)](i)) in canine pulmonary arterial smooth muscle cells (PASMCs). [Ca(2+)](i) was measured as the 340- to 380-nm ratio in individual fura 2-loaded PASMCs. Resting [Ca(2+)](i) was 96 +/- 4 nmol/l. PE (10 micromol/l) stimulated oscillations in [Ca(2+)](i), with a peak amplitude of 437 +/- 22 nmol/l and a frequency of 1.01 +/- 0.12/min. Thapsigargin (1 micromol/l) was used to deplete sarcoplasmic reticulum (SR) Ca(2+) after extracellular Ca(2+) was removed. Under these conditions, a nifedipine-insensitive, sustained increase in [Ca(2+)](i) (140 +/- 7% of control value) was observed when the extracellular Ca(2+) concentration was restored; i.e., capacitative Ca(2+) entry was demonstrated. Capacitative Ca(2+) entry also refilled SR Ca(2+) stores. Capacitative Ca(2+) entry was attenuated (32 +/- 3% of control value) by 50 micromol/l of SKF-96365 (a nonselective Ca(2+)-channel inhibitor). Tyrosine kinase inhibition with tyrphostin 23 (100 micromol/l) and genistein (100 micromol/l) also inhibited capacitative Ca(2+) entry to 63 +/- 12 and 85 +/- 4% of control values, respectively. SKF-96365 (30 micromol/l) attenuated both the amplitude (15 +/- 7% of control value) and frequency (50 +/- 21% of control value) of PE-induced Ca(2+) oscillations. SKF-96365 (50 micromol/l) abolished the oscillations. Tyrphostin 23 (100 micromol/l) also inhibited the amplitude (17 +/- 7% of control value) and frequency (45 +/- 9% of control value) of the oscillations. Genistein (30 micromol/l) had similar effects. Both SKF-96365 and tyrphostin 23 attenuated PE-induced contraction in isolated pulmonary arterial rings. These results demonstrate that capacitative Ca(2+) entry is present and capable of refilling SR Ca(2+) stores in canine PASMCs and may be involved in regulating PE-induced Ca(2+) oscillations. A tyrosine kinase is involved in the signal transduction pathway for alpha(1)-adrenoreceptor activation in PASMCs.
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Affiliation(s)
- S Doi
- Center for Anesthesiology Research, Division of Anesthesiology and Critical Care Medicine, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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Waugh DJ, Gaivin RJ, Damron DS, Murray PA, Perez DM. Binding, partial agonism, and potentiation of alpha(1)-adrenergic receptor function by benzodiazepines: A potential site of allosteric modulation. J Pharmacol Exp Ther 1999; 291:1164-71. [PMID: 10565838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
Benzodiazepines, a class of drugs commonly used to induce anesthesia and sedation, can attenuate intracellular calcium oscillations evoked by alpha(1)-adrenergic receptor (alpha(1)-AR) stimulation in pulmonary artery smooth muscle cells. We postulated a direct action of benzodiazepines in modulating alpha(1)-AR function at the receptor level. Benzodiazepines bound to each of the cloned alpha(1)-AR subtypes (alpha(1a)-, alpha(1b)-, or alpha(1d)-AR) on COS-1 cell membranes transiently transfected to express a single population of alpha(1)-AR subtype. The ability of benzodiazepines to alter alpha(1)-AR signal transduction was investigated by measuring total inositol phosphate generation in rat-1 fibroblast cells, stably transfected to express a single alpha(1)-AR subtype. By themselves, benzodiazepines displayed partial agonism. At alpha(1b)-ARs and alpha(1d)-ARs, the maximal inositol phosphate response to phenylephrine was potentiated almost 2-fold by either midazolam or lorazepam (100 microM). At alpha(1a)-ARs, diazepam, lorazepam, and midazolam all increased the maximal response of the partial agonist clonidine at these receptors, whereas the response to the full agonist phenylephrine was unaltered or inhibited. The potentiating actions of midazolam and its partial agonism at alpha(1)-ARs was blocked by the addition of 1 microM prazosin, an alpha(1)-AR antagonist, and not by a gamma-aminobutyric acid(A)-receptor antagonist. These studies show that benzodiazepines modulate the function of alpha(1)-ARs in vitro, and this is the first report of a potential allosteric site on alpha(1)-ARs that may be therapeutically useful for drug design.
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Affiliation(s)
- D J Waugh
- Department of Molecular Cardiology, The Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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Ruehr ML, Zakhary DR, Damron DS, Bond M. Cyclic AMP-dependent protein kinase binding to A-kinase anchoring proteins in living cells by fluorescence resonance energy transfer of green fluorescent protein fusion proteins. J Biol Chem 1999; 274:33092-6. [PMID: 10551879 DOI: 10.1074/jbc.274.46.33092] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A-kinase anchoring proteins tether cAMP-dependent protein kinase (PKA) to specific subcellular locations. The purpose of this study was to use fluorescence resonance energy transfer to monitor binding events in living cells between the type II regulatory subunit of PKA (RII) and the RII-binding domain of the human thyroid RII anchoring protein (Ht31), a peptide containing the PKA-binding domain of an A-kinase anchoring protein. RII was linked to enhanced yellow fluorescent protein (EYFP), Ht31 was linked to enhanced cyan fluorescent protein (ECFP), and these constructs were coexpressed in Chinese hamster ovary cells. Upon excitation of the donor fluorophore, Ht31.ECFP, an increase in emission of the acceptor fluorophore, RII.EYFP, and a decrease in emission from Ht31.ECFP were observed. The emission ratio (acceptor/donor) was increased 2-fold (p < 0.05) in cells expressing Ht31.ECFP and RII.EYFP compared with cells expressing Ht31P.ECFP, the inactive form of Ht31, and RII.EYFP. These results provide the first in vivo demonstration of RII/Ht31 interaction in living cells and confirm previous in vitro findings of RII/Ht31 binding. Using surface plasmon resonance, we also showed that the green fluorescent protein tags did not significantly alter the binding of Ht31 to RII. Thus, fluorescence resonance energy transfer can be used to directly monitor protein-protein interactions of the PKA signaling pathway in living cells.
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Affiliation(s)
- M L Ruehr
- Department of Molecular Cardiology, Lerner Research Institute, Case Western Reserve University School of Medicine, Cleveland, Ohio 44195, USA
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Kanaya N, Zakhary DR, Murray PA, Damron DS. Differential effects of fentanyl and morphine on intracellular Ca2+ transients and contraction in rat ventricular myocytes. Anesthesiology 1998; 89:1532-42. [PMID: 9856730 DOI: 10.1097/00000542-199812000-00033] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Our objective was to elucidate the direct effects of fentanyl and morphine on cardiac excitation-contraction coupling using individual, field-stimulated rat ventricular myocytes. METHODS Freshly isolated myocytes were loaded with fura-2 and field stimulated (0.3 Hz) at 28 degrees C. Amplitude and timing of intracellular Ca2+ concentration (at a 340:380 ratio) and myocyte shortening (video edge detection) were monitored simultaneously in individual cells. Real time Ca2+ uptake into isolated sarcoplasmic reticulum vesicles was measured using fura-2 free acid in the extravesicular compartment. RESULTS The authors studied 120 cells from 30 rat hearts. Fentanyl (30-1,000 nM) caused dose-dependent decreases in peak intracellular Ca2+ concentration and shortening, whereas morphine (3-100 microM) decreased shortening without a concomitant decrease in the Ca2+ transient. Fentanyl prolonged the time to peak and to 50% recovery for shortening and the Ca2+ transient, whereas morphine only prolonged the timing parameters for shortening. Morphine (100 microM), but not fentanyl (1 microM), decreased the amount of Ca2+ released from intracellular stores in response to caffeine in intact cells, and it inhibited the rate of Ca2+ uptake in isolated sarcoplasmic reticulum vesicles. Fentanyl and morphine both caused a downward shift in the dose-response curve to extracellular Ca2+ for shortening, with no concomitant effect on the Ca2+ transient. CONCLUSIONS Fentanyl and morphine directly depress cardiac excitation-contraction coupling at the cellular level. Fentanyl depresses myocardial contractility by decreasing the availability of intracellular Ca2+ and myofilament Ca2+ sensitivity. In contrast, morphine depresses myocardial contractility primarily by decreasing myofilament Ca2+ sensitivity.
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Affiliation(s)
- N Kanaya
- Center for Anesthesiology Research, Cleveland Clinic Foundation, Ohio 44195, USA
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Abstract
BACKGROUND Myocardial contractility is regulated by intracellular concentration of free Ca2+ ([Ca2'],) and myofilament Ca2+ sensitivity. The objective of this study was to elucidate the direct effects of thiopental on cardiac excitation-contraction coupling using individual, field-stimulated ventricular myocytes. METHODS Freshly isolated rat ventricular myocytes were loaded with the Ca2+ indicator, fura-2, and placed on the stage of an inverted fluorescence microscope in a temperature-regulated bath. [Ca2+], (340/380 ratio) and myocyte shortening (video-edge detection) were monitored simultaneously in individual cells field-stimulated at 0.3 Hz. Amplitude and timing of myocyte shortening and [Ca2+l, were compared before and after addition of thiopental. Intracellular pH was measured with the pH indicator, BCECF (500/440 ratio). Real-time uptake of Ca2+ into isolated sarcoplasmic reticulum vesicles was measured using fura-2 free acid in the extravesicular compartment. One hundred thirty-two cells were studied. RESULTS Field stimulation increased [Ca2+]i from 85 + 10 nM to 355 + 22 nM (mean + SEM). Myocytes shortened by 10% of resting cell length (127 + 5 tlm). Times to peak [Ca2+], and shortening were 139 + 6 and 173 + 7 msec, respectively. Times to 50% recovery for [Ca2+], and shortening were 296 + 6 and 290 + 6 ms, respectively. Addition of thiopental (30-1,000 /lM) resulted in dose-dependent decreases in peak [Ca2+]i and myocyte shortening. Thiopental altered time to peak and time to 50% recovery for [Ca2+], and myocyte shortening and inhibited the rate of uptake of Ca2+ into isolated sarcoplasmic reticulum vesicles. Thiopental did not, however, alter the amount of Ca2+ released in response to caffeine in sarcoplasmic reticulum vesicles or intact cells. Thiopental (100 uM) increased intracellular pH and caused an upward shift in the dose-response curve to extracellular Ca2+ for shortening, with no concomitant effect on peak [Ca2+],. These effects were abolished by ethylisopropyl amiloride, an inhibitor of Na+-H+ exchange. CONCLUSION Thiopental has a direct negative inotropic effect on cardiac excitation-contraction coupling at the cellular level, which is mediated by a decrease in [Ca2+],. Thiopental also increases myofilament Ca2+ sensitivity via alkalinization of the cell, which may partially offset its negative inotropic effect.
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Affiliation(s)
- N Kanaya
- Center for Anesthesiology Research, The Cleveland Clinic Foundation, Ohio 44195, USA
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