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Spies PE, Beune TNN, Heesakkers J, van Munster BC, Claassen JAHR. Orthostatic blood pressure recovery in older males using alpha-blockers for lower urinary tract symptoms, an explorative study in a urology outpatient clinic. J Clin Pharm Ther 2022; 47:1698-1703. [PMID: 35777069 DOI: 10.1111/jcpt.13726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 05/31/2022] [Accepted: 06/14/2022] [Indexed: 11/30/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE Alpha-blockers have been associated with orthostatic hypotension (OH). We aimed to assess the prevalence of OH measured with beat-to-beat blood pressure monitoring in older male outpatients who used alpha-blockers for lower urinary tract symptoms (LUTS). In addition, we investigated associations of OH with duration of alpha-blocker use, concomitant medication use and comorbidity. METHODS Cross-sectional explorative study in a urology outpatient clinic. Older white males ≥65 years using alpha-blockers for LUTS were included. Blood pressure responses to standing up from supine were recorded using a validated beat-to-beat blood pressure device (Finapres). Prevalence rates were derived from the beat-to-beat data to include OH measured between 60-110 s (OH), impaired recovery OH at 40 s (OH[40]), initial OH (IOH) and normal orthostatic response. Subgroups were defined based on duration of alpha-blocker use, polypharmacy, and Charlson comorbidity index (CCI), to obtain relative risks. RESULTS AND DISCUSSION Sixty-five patients were included. Median age was 75 years (range 65-92). The prevalence of OH was 7.7% (n = 5). The prevalence of OH(40) was 16.9% (n = 11) and of IOH 38.5% (n = 25). Thirty-six patients (55.4%) had a normal orthostatic response. The relative risk of OH for the subgroup using ≥ $$ \ge $$ 10 medications (n = 13) was 6.0 (95%CI 1.1-32.3). For the subgroup with multimorbidity (CCI ≥3, n = 11) this was 7.4 (95%CI 1.4-39.0). Recent initiation of alpha-blocker use (<3 months) did not increase OH risk (RR 0.6 [95%CI 0.1-5.1]). WHAT IS NEW AND CONCLUSION The overall prevalence of OH was low and comparable to age-matched population prevalence, suggesting that the relative contribution of alpha-blockers to OH was small. However, OH risk significantly increased in patients with multimorbidity or polypharmacy. For these patients, the benefits of starting alpha-blockers for LUTS should be weighed against the increased risk of OH.
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Affiliation(s)
- Petra E Spies
- Dept. of Geriatric Medicine, Gelre Ziekenhuizen, Apeldoorn & Zutphen, Zutphen, The Netherlands.,Centre of Excellence for Old Age Medicine, Gelre ziekenhuizen, Apeldoorn & Zutphen, Zutphen, The Netherlands
| | - Thimpe N N Beune
- Dept. of Geriatric Medicine, Gelre Ziekenhuizen, Apeldoorn & Zutphen, Zutphen, The Netherlands.,Centre of Excellence for Old Age Medicine, Gelre ziekenhuizen, Apeldoorn & Zutphen, Zutphen, The Netherlands
| | - John Heesakkers
- Dept. of Urology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Barbara C van Munster
- Centre of Excellence for Old Age Medicine, Gelre ziekenhuizen, Apeldoorn & Zutphen, Zutphen, The Netherlands.,Department of Internal Medicine and Geriatrics, Groningen, University of Groningen, University Medical Centre Groningen, Groningen, The Netherlands
| | - Jurgen A H R Claassen
- Dept. of Geriatric Medicine, Radboud University Medical Centre, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
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Morrison K, Haag F, Ernst R, Iglarz M, Clozel M. Selective Prostacyclin Receptor Agonist Selexipag, in Contrast to Prostacyclin Analogs, Does Not Evoke Paradoxical Vasoconstriction of the Rat Femoral Artery. J Pharmacol Exp Ther 2018; 365:727-733. [PMID: 29588339 DOI: 10.1124/jpet.117.246058] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 03/16/2018] [Indexed: 12/14/2022] Open
Abstract
Selexipag [2-{4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}-N-(methylsulfonyl)acetamide] is a selective nonprostanoid prostacyclin (PGI2) receptor (IP receptor) agonist that is approved for the treatment of pulmonary arterial hypertension (PAH). In contrast to selexipag, PGI2 analogs used in the clinic are nonselective agonists at prostanoid receptors and can also activate contractile prostaglandin E receptor 3 (EP3) receptors. Leg pain is a common side effect in patients receiving treatment with PGI2 analogs and peripheral vasoconstriction can be responsible for side effects related to muscular ischemia. This study tested the hypothesis that PGI2 analogs could cause paradoxical vasoconstriction of the femoral artery via EP3 receptor activation but that only vasorelaxation would be observed in response to selexipag and its active metabolite ACT-333679 [{4-[(5,6-diphenylpyrazin-2-yl)(isopropyl)amino]butoxy}acetic acid]. Selexipag and ACT-333679 relaxed rings of the isolated rat femoral artery contracted with either prostaglandin F2α (PGF2α ) or the α1 adrenoceptor (α1AR) agonist phenylephrine. ACT-333679 also inhibited contraction of the femoral artery to sympathetic nerve stimulation. In contrast, PGI2 analogs (iloprost, beraprost, and treprostinil) caused additional contraction of arterial rings precontracted with phenylephrine, which was reverted to relaxation by antagonism of EP3 receptors. Treprostinil augmented contraction of the femoral artery to sympathetic nerve stimulation in an EP3 receptor-dependent manner. Mechanistically, concomitant EP3 and α1AR receptor activation synergistically constricted femoral arteries. It is concluded that selexipag and ACT-333679 are vasorelaxants of the rat femoral artery and, unlike PGI2 analogs, do not cause paradoxical vasoconstriction via activation of EP3 receptors. EP3 receptor-mediated vasoconstriction may contribute to the well documented peripheral muscle pain reported in patients with PAH receiving PGI2 analogs. Leg pain may be less in patients treated with selexipag.
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Affiliation(s)
- Keith Morrison
- Drug Discovery Department, Idorsia Pharmaceuticals Ltd., Allschwil, Switzerland
| | - Franck Haag
- Drug Discovery Department, Idorsia Pharmaceuticals Ltd., Allschwil, Switzerland
| | - Roland Ernst
- Drug Discovery Department, Idorsia Pharmaceuticals Ltd., Allschwil, Switzerland
| | - Marc Iglarz
- Drug Discovery Department, Idorsia Pharmaceuticals Ltd., Allschwil, Switzerland
| | - Martine Clozel
- Drug Discovery Department, Idorsia Pharmaceuticals Ltd., Allschwil, Switzerland
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Al Dera H, Brock JA. Changes in sympathetic neurovascular function following spinal cord injury. Auton Neurosci 2017; 209:25-36. [PMID: 28209424 DOI: 10.1016/j.autneu.2017.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 01/31/2017] [Accepted: 02/09/2017] [Indexed: 12/31/2022]
Abstract
The effects of spinal cord injury (SCI) on sympathetic neurovascular transmission have generally been ignored. This review describes changes in sympathetic nerve-mediated activation of arterial vessels to which ongoing sympathetic activity has been reduced or silenced following spinal cord transection in rats. In all vessels studied in rats, SCI markedly enhanced their contractile responses to nerve activity. However, the mechanisms that augment neurovascular transmission differ between the rat tail artery and mesenteric artery. In tail artery, the enhancement of neurovascular transmission cannot be attributed to changes in sensitivity of the vascular muscle to α1- or α2-adrenoceptor agonists. Instead the contribution of L-type Ca2+ channels to activation of the smooth muscle by nerve-released noradrenaline is greatly increased following SCI. By contrast, mesenteric arteries from SCI rats had increased sensitivity to phenylephrine but not to methoxamine. While both phenylephrine and methoxamine are α1-adrenoceptor agonists, only phenylephrine is a substrate for the neuronal noradrenaline transporter. Therefore the selective increase in sensitivity to phenylephrine suggests that the activity of the neuronal noradrenaline transporter is reduced. While present evidence suggests that sympathetic vasoconstrictor neurons do not contribute to the normal regulation of peripheral resistance below a complete SCI in humans, the available evidence does indicate that these experimental findings in animals are likely to apply after SCI in humans and contribute to autonomic dysreflexia.
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Affiliation(s)
- Hussain Al Dera
- Basic Medical Sciences, College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - James A Brock
- Department of Anatomy and Neuroscience, University of Melbourne, Victoria 3010, Australia.
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Fotso Soh J, Strong HR, Daneshtalab N, Tabrizchi R. The effect of inflammation on sympathetic nerve mediated contractions in rat isolated caudal artery. Eur J Pharmacol 2016; 792:54-62. [PMID: 27793651 DOI: 10.1016/j.ejphar.2016.10.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 10/19/2016] [Accepted: 10/21/2016] [Indexed: 10/20/2022]
Abstract
Chronic inflammatory process(es) contributes to changes in vascular function in a variety of diseases. Sympathetic nerve-mediated responses in blood vessels play a pivotal role in regular physiological functions. We tested the hypothesis that sympathetic neuro-effector function will be altered as consequence of inflammatory state. Sympathetic nerve-mediated contractions and alpha adrenergic receptor expressions were evaluated in isolated caudal arteries of rats treated with saline and Complete Freund's adjuvant (CFA). While CFA-treated animals had significantly higher plasma levels of tumor necrosis factor-alpha compared to saline, blood pressure remained unchanged. Immunofluorescence revealed increased expression of ionized calcium adapter binding molecule-1 in the adventitia of blood vessels from CFA-treated animals compared to saline. In isolated arteries, electrical field stimulations between 1.25 and 40Hz resulted in frequency-dependent contractions that wasabolished by tetrodotoxin. Neurogenic contractions from CFA groups were significantly greater than saline. While the presence of alpha1-adrenoceptor antagonist (prazosin) significantly inhibited contractions at lower frequencies of stimulation (1.25-5Hz) in isolated arteries of CFA-treated rats compared to controls, alpha2-adrenoceptor antagonist (rauwolscine) had modest effects. Inhibition of neuronal reuptake by cocaine comparably enhanced field-stimulated responses in vessels of experimental and control animals. Immunofluorescence revealed a difference in expression of alpha1- and alpha2-adrenoceptors in the endothelium of blood vessels of CFA compared to saline controls. Collectively, our observations lend support to enhanced neurogenic contractions in blood vessels of inflamed animals possibly attributing to alterations in responsiveness and/or distribution of post-junctional alpha1-adrenoceptors.
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Affiliation(s)
- Jocelyn Fotso Soh
- Division of BioMedical Sciences, Faculty of Medicine Memorial University, St. John's, NL, Canada
| | - Hilary R Strong
- Division of BioMedical Sciences, Faculty of Medicine Memorial University, St. John's, NL, Canada
| | - Noriko Daneshtalab
- Division of BioMedical Sciences, Faculty of Medicine Memorial University, St. John's, NL, Canada; School of Pharmacy Memorial University, St. John's, NL, Canada.
| | - Reza Tabrizchi
- Division of BioMedical Sciences, Faculty of Medicine Memorial University, St. John's, NL, Canada.
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Martínez AC, Hernández M, Novella S, Martínez MP, Pagán RM, Hermenegildo C, García-Sacristán A, Prieto D, Benedito S. Diminished neurogenic femoral artery vasoconstrictor response in a Zucker obese rat model: differential regulation of NOS and COX derivatives. PLoS One 2014; 9:e106372. [PMID: 25216050 PMCID: PMC4162543 DOI: 10.1371/journal.pone.0106372] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 08/03/2014] [Indexed: 01/21/2023] Open
Abstract
Objective Peripheral arterial disease is one of the macrovascular complications of type 2 diabetes mellitus. This study addresses femoral artery regulation in a prediabetic model of obese Zucker rats (OZR) by examining cross-talk between endothelial and neural factors. Methods and Results Arterial preparations from lean (LZR) and OZR were subjected to electrical field stimulation (EFS) on basal tone. Nitric oxide synthase (NOS) and cyclooxygenase (COX) isoform expression patterns were determined by immunohistochemical labelling and Western blotting. Results indicate significantly reduced noradrenergic contractions in preparations from OZR compared with those of LZR. Functional inhibition of endothelial NOS (eNOS) indicated a predominant role of this isoform in LZR and its modified activity in OZR. Neural (nNOS) and inducible NOS (iNOS) were activated and their expression was higher in femoral arteries from OZR. Neurotransmission modulated by large-conductance Ca2+-activated (BKCa) or voltage-dependent (KV) K+ channels did not seem compromised in the obese animals. Endothelial COX-1 and COX-2 were expressed in LZR and an additional adventitial location of COX-2 was also observed in OZR, explaining the higher COX-2 protein levels detected in this group. Prostanoids derived from both isoforms helped maintain vasoconstriction in LZR while in OZR only COX-2 was active. Superoxide anion inhibition reduced contractions in endothelium-intact arteries from OZR. Conclusions Endothelial dysfunction led to reduced neurogenic vasoconstriction in femoral arteries from OZR. In a setting of obesity, NO-dependent nNOS and iNOS dilation activity could be an alternative mechanism to offset COX-2- and reactive oxygen species-mediated vasoconstriction, along with impaired endothelial NO relaxation.
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Affiliation(s)
- Ana Cristina Martínez
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Medardo Hernández
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Susana Novella
- Departamento de Fisiología, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
| | - María Pilar Martínez
- Departamento de Anatomía y Anatomía Patológica Comparadas, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain
| | - Rosa María Pagán
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Carlos Hermenegildo
- Departamento de Fisiología, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
| | - Albino García-Sacristán
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Dolores Prieto
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Sara Benedito
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
- * E-mail:
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Westcott EB, Segal SS. Perivascular innervation: a multiplicity of roles in vasomotor control and myoendothelial signaling. Microcirculation 2013; 20:217-38. [PMID: 23289720 DOI: 10.1111/micc.12035] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 12/25/2012] [Indexed: 12/30/2022]
Abstract
The control of vascular resistance and tissue perfusion reflect coordinated changes in the diameter of feed arteries and the arteriolar networks they supply. Against a background of myogenic tone and metabolic demand, vasoactive signals originating from perivascular sympathetic and sensory nerves are integrated with endothelium-derived signals to produce vasodilation or vasoconstriction. PVNs release adrenergic, cholinergic, peptidergic, purinergic, and nitrergic neurotransmitters that lead to SMC contraction or relaxation via their actions on SMCs, ECs, or other PVNs. ECs release autacoids that can have opposing actions on SMCs. Respective cell layers are connected directly to each other through GJs at discrete sites via MEJs projecting through holes in the IEL. Whereas studies of intercellular communication in the vascular wall have centered on endothelium-derived signals that govern SMC relaxation, attention has increasingly focused on signaling from SMCs to ECs. Thus, via MEJs, neurotransmission from PVNs can evoke distinct responses from ECs subsequent to acting on SMCs. To integrate this emerging area of investigation in light of vasomotor control, the present review synthesizes current understanding of signaling events that originate within SMCs in response to perivascular neurotransmission in light of EC feedback. Although often ignored in studies of the resistance vasculature, PVNs are integral to blood flow control and can provide a physiological stimulus for myoendothelial communication. Greater understanding of these underlying signaling events and how they may be affected by aging and disease will provide new approaches for selective therapeutic interventions.
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Affiliation(s)
- Erika B Westcott
- Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri 65212, USA
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Zacharia J, Mauban JRH, Raina H, Fisher SA, Wier WG. High vascular tone of mouse femoral arteries in vivo is determined by sympathetic nerve activity via α1A- and α1D-adrenoceptor subtypes. PLoS One 2013; 8:e65969. [PMID: 23776582 PMCID: PMC3680395 DOI: 10.1371/journal.pone.0065969] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 05/02/2013] [Indexed: 02/04/2023] Open
Abstract
Background and purpose Determining the role of vascular receptors in vivo is difficult and not readily accomplished by systemic application of antagonists or genetic manipulations. Here we used intravital microscopy to measure the contributions of sympathetic receptors, particularly α1-adrenoceptor subtypes, to contractile activation of femoral artery in vivo. Experimental approach Diameter and intracellular calcium ([Ca2+]i) in femoral arteries were determined by intravital fluorescence microscopy in mice expressing a Myosin Light Chain Kinase (MLCK) based calcium-calmodulin biosensor. Pharmacological agents were applied locally to the femoral artery to determine the contributions of vascular receptors to tonic contraction and [Ca2+]i,. Key results In the anesthetized animal, femoral arteries were constricted to a diameter equal to 54% of their passive diameter (i.e. tone = 46%). Of this total basal tone, 16% was blocked by RS79948 (0.1 µM) and thus attributable to α2-adrenoceptors. A further 46% was blocked by prazosin (0.1 µM) and thus attributable to α1-adrenoceptors. Blockade of P2X and NPY1 receptors with suramin (0.5 mM) and BIBP3226 (1.0 µM) respectively, reduced tone by a further 22%, leaving 16% of basal tone unaffected at these concentrations of antagonists. Application of RS100329 (α1A-selective antagonist) and BMY7378 (α1D-selective) decreased tone by 29% and 26%, respectively, and reduced [Ca2+]i. Chloroethylclonidine (1 µM preferential for α1B-) had no effect. Abolition of sympathetic nerve activity (hexamethonium, i.p.) reduced basal tone by 90%. Conclusion and Implications Tone of mouse femoral arteries in vivo is almost entirely sympathetic in origin. Activation of α1A- and α1D-adrenoceptors elevates [Ca2+]i and accounts for at least 55% of the tone.
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Affiliation(s)
- Joseph Zacharia
- University of Maryland, School of Medicine, Baltimore, Maryland, United States of America.
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Tripovic D, McLachlan EM, Brock JA. Removal of half the sympathetic innervation does not reduce vasoconstrictor responses in rat tail artery. J Physiol 2013; 591:2867-84. [PMID: 23551946 DOI: 10.1113/jphysiol.2012.250365] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Following reinnervation of denervated rat tail arteries, nerve-evoked contractions are at least as large as those evoked in normally innervated arteries despite a much lower nerve terminal density. Here nerve-evoked contractions have been investigated after transection of half the sympathetic innervation of normal tail arteries. After 1 week, the noradrenergic plexus 50-70 mm along the tail was about half as dense as control. Excitatory junction potentials recorded in smooth muscle cells of arterial segments isolated in vitro were half their normal amplitude. Surprisingly, nerve-evoked contractions of isometrically mounted segments were not reduced in amplitude, as was also the case after only 3 days. After 1 week, enhancement of nerve-evoked contractions by blocking either neuronal re-uptake of noradrenaline with desmethylimipramine or prejunctional α2-adrenoceptors with idazoxan was similar to control, suggesting that these mechanisms are matched to the number of innervating axons. The relative contribution of postjunctional α2-adrenoceptors to contractions evoked by long trains of stimuli was enhanced but that of α1-adrenoceptors was unchanged. Transiently, sensitivity to the α1-adrenoceptor agonist phenylephrine was slightly increased. After 7 weeks, amplitudes of nerve-evoked contractions remained similar to control, and sensitivity to phenylephrine had recovered but that to the α2-adrenoceptor agonist clonidine was slightly raised. The normal amplitude of nerve-evoked contractions after partial denervation is only partly explained by the greater contribution of α2-adrenoceptors. While the post-receptor mechanisms activated by nerve-released transmitter may be modified to amplify the contractions after partial denervation, our findings suggest that these mechanisms are normally saturated, at least in this artery.
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Affiliation(s)
- Diana Tripovic
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Vic. 3010, Australia
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López-Islas I, López-Sánchez P, Ibarra M, Gallardo-Ortiz IA, Terrón JA. Effect of inter-renal aortic coarctation-induced hypertension on function and expression of vascular α(1A)- and α(1D)-adrenoceptors. Can J Physiol Pharmacol 2011; 90:1-12. [PMID: 22149309 DOI: 10.1139/y11-099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated the effect of inter-renal aortic coarctation on the function and expression of vascular α(1A)- and α(1D)-adrenoceptors and plasma angiotensin II (ATII) in rats. Male Wistar rats, either sham operated (SO), or with aortic coarctation for 7 (AC7) and 14 days (AC14) were used for agonist-induced pressor responses in vehicle (physiological saline)- and antagonist-treated anesthetized animals, immunoblot analysis (α(1A)- and α(1D)-adrenoceptor in aorta and caudal arteries), and immunoassay (plasma ATII). The α(1D)-adrenoceptor antagonist, BMY-7378 (BMY) blocked noradrenaline-induced responses in the order SO > AC7 ≫ AC14; in contrast, the α(1A)-adrenoceptor antagonist RS-100329 (RS), produced a marginal shift to the right of the dose-response curve to noradrenaline, along with a strong decrease of the maximum pressor effect in the order SO > AC7 = AC14. The potency of the α(1A)-adrenoceptor agonist A-61603 increased in rats with AC14, and responses were inhibited by RS in the order AC14 > AC7 > SO. In aorta, α(1D)-adrenoceptor protein increased in AC7 and decreased in AC14; α(1A)-adrenoreceptor protein increased in the caudal artery of AC7 and returned to control values in AC14. Plasma ATII increased in AC7 and AC14, compared with SO rats. These results suggest an early and direct relationship between ATII and α(1D)-adrenoreceptors in the development of hypertension in this experimental model.
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Affiliation(s)
- Inés López-Islas
- Departamento de Farmacología, Centro de Investigación y de Estudios Avanzados del IPN, Apartado postal 14-740, Zacatenco 07000, México DF, Mexico
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Martínez AC, Pagán RM, Prieto D, Recio P, García-Sacristán A, Hernández M, Benedito S. Modulation of noradrenergic neurotransmission in isolated rat radial artery. J Pharmacol Sci 2010; 111:299-311. [PMID: 19926936 DOI: 10.1254/jphs.09135fp] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
The present study was designed to characterize the neurogenic contraction of rat radial artery. Electrical field stimulation (EFS) evoked frequency-dependent contraction that was abolished by tetrodotoxin (neuronal Na(+) channel blocker), guanethidine (sympathetic neuron blocker), or phentolamine (alpha-adrenoceptor blocker). The alpha(1)-adrenoceptor antagonist prazosin inhibited endothelium-independent contractions to EFS, noradrenaline (NA), and the alpha(1)-adrenoceptor agonist phenylephrine. Rauwolscine, an alpha(2)-adrenoceptor antagonist, augmented nerve-mediated contractions and reduced sensitivity to NA and the alpha(2)-adrenoceptor agonist BHT-920. The beta-adrenoceptor antagonist propranolol diminished EFS-elicited contractions, while sensitivity to NA was enhanced by propranolol. Relaxations evoked by isoproterenol, a beta-adrenoceptor agonist, were abolished by propranolol. N(G)-Nitro-L-arginine (L-NOARG), a nitric oxide (NO) synthase inhibitor, increased both nerve-mediated and NA-induced responses in endothelium-intact, but not in endothelium-denuded arteries. Moreover, endothelium-dependent responses to BHT-920 and isoproterenol were modified by L-NOARG. Tetraethylammonium (TEA) or 4-aminopyridine, the Ca2+-activated (K(Ca)) or voltage-dependent K+ (K(V)) channel blockers, respectively, enhanced the neurogenic contractions observed. TEA but not 4-aminopyridine increased NA-induced contractions. The ATP-sensitive K+ (K(ATP))-channel blocker glibenclamide failed to modify adrenergic contractions. Blockade of capsaicin-sensitive primary afferents increased EFS-induced contractions. In conclusion, adrenergic contractions are predominantly mediated by muscular alpha(1)-adrenoceptors, while endothelial alpha(2)- and beta-adrenoceptors play a minor role. Presynaptic alpha(2)- and beta-adrenoceptors cannot be precluded. Noradrenergic neurotransmission in rat radial artery seems to be modulated by both stimulation of endothelial NO, K(Ca), and K(V) channels and sensory C-fiber activation.
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Methven L, McBride M, Wallace GA, McGrath JC. The alpha 1B/D-adrenoceptor knockout mouse permits isolation of the vascular alpha 1A-adrenoceptor and elucidates its relationship to the other subtypes. Br J Pharmacol 2009; 158:209-24. [PMID: 19572943 PMCID: PMC2795267 DOI: 10.1111/j.1476-5381.2009.00269.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Revised: 01/30/2009] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Mesenteric and carotid arteries from the alpha(1B/D)-adrenoceptor knockout (alpha(1B/D)-KO) were employed to isolate alpha(1A)-adrenoceptor pharmacology and location and to reveal these features in the wild-type (WT) mouse. EXPERIMENTAL APPROACH Functional pharmacology by wire myography and receptor localization by confocal microscopy, using the fluorescent alpha(1)-adrenoceptor ligand BODIPY FL-Prazosin (QAPB), on mesenteric (an 'alpha(1A)-adrenoceptor' tissue) and carotid (an 'alpha(1D)-adrenoceptor' tissue) arteries. KEY RESULTS Alpha(1B/D)-KO mesenteric arteries showed straightforward alpha(1A)-adrenoceptor agonist/antagonist pharmacology. WT had complex pharmacology with alpha(1A)- and alpha(1D)-adrenoceptor components. alpha(1B/D)-KO had a larger alpha(1A)-adrenoceptor response suggesting compensatory up-regulation: no increase in fluorescent ligand binding suggests up-regulation of signalling. alpha(1B/D)-KO carotid arteries had low efficacy alpha(1A)-adrenoceptor responses. WT had complex pharmacology consistent with co-activation of all three subtypes. Fluorescent binding had straightforward alpha(1A)-adrenoceptor characteristics in both arteries of alpha(1B/D)-KO. Fluorescent binding varied between cells in relative intracellular and surface distribution. Total fluorescence was reduced in the alpha(1B/D)-KO due to fewer smooth muscle cells showing fluorescent binding. WT binding was greater and sensitive to alpha(1A)- and alpha(1D)-adrenoceptor antagonists. CONCLUSIONS AND IMPLICATIONS The straightforward pharmacology and fluorescent binding in the alpha(1B/D)-KO was used to interpret the properties of the alpha(1A)-adrenoceptor in the WT. Reduced total fluorescence in alpha(1B/D)-KO arteries, despite a clear difference in the functionally dominant subtype, indicates that measurement of receptor protein is unlikely to correlate with function. Fewer cells bound QAPB in the alpha(1B/D)-KO suggesting different cellular phenotypes of alpha(1A)-adrenoceptor exist. The alpha(1B/D)-KO provides robust assays for the alpha(1A)-adrenoceptor and takes us closer to understanding multi-receptor subtype interactions.
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MESH Headings
- Adrenergic Agonists/pharmacology
- Adrenergic Antagonists/pharmacology
- Adrenergic alpha-1 Receptor Agonists
- Animals
- Carotid Arteries/drug effects
- Carotid Arteries/physiology
- Male
- Mesenteric Arteries/drug effects
- Mesenteric Arteries/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Protein Subunits/classification
- Protein Subunits/physiology
- Receptors, Adrenergic, alpha-1/classification
- Receptors, Adrenergic, alpha-1/deficiency
- Receptors, Adrenergic, alpha-1/physiology
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Affiliation(s)
- L Methven
- Integrative and Systems Biology, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK.
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Khan AH, Sattar MA, Abdullah NA, Johns EJ. EFFECT OF CALCIUM CHANNEL BLOCKADE ON ADRENERGICALLY INDUCED RENAL VASOCONSTRICTION IN RAT MODELS OF RENAL IMPAIRMENT. Clin Exp Pharmacol Physiol 2009; 36:501-8. [DOI: 10.1111/j.1440-1681.2008.05098.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Ameer O, Salman I, Siddiqui MJ, Yam M, Sriramanen R, Mutee A, Sadikun A, Ismail Z, Asmawi M. Vascular Responsiveness to Macrosolen cochinchinensis Extracts inIsolated Rat Thoracic Aorta. INT J PHARMACOL 2009. [DOI: 10.3923/ijp.2009.191.199] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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15
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Comparison of the binding affinity of CGP-12177A at recombinant rat alpha(1D)-adrenoceptors expressed in BHK-21 cell membranes and alpha(1)-adrenoceptors present in rat cerebral cortex membranes. Eur J Pharmacol 2008; 590:303-9. [PMID: 18589413 DOI: 10.1016/j.ejphar.2008.05.046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 05/07/2008] [Accepted: 05/30/2008] [Indexed: 11/24/2022]
Abstract
Recent in vitro studies, performed in rat aorta, mesenteric and intrapulmonary arteries, and human pulmonary artery, demonstrated that the beta-adrenoceptor ligand CGP-12177A (4-[3-[(1,1-dimethylethyl)amino]-2-hydroxypropoxy]-1,3-dihydro-2H-benzimidazol-2-one) is also provided with antagonist or partial agonist properties at alpha(1)-adrenoceptors. These observations were supported by estimates of CGP-12177A binding affinity at alpha(1)-adrenoceptors, which have been always performed in rat cerebral cortex membranes, as a surrogate of vascular tissue. Since alpha(1D)-adrenoceptors are predominant in both rat aorta and mesenteric artery, in the present study, we measured, for the first time, the binding affinity of CGP-12177A at recombinant rat alpha(1D)-adrenoceptors expressed in BHK-21 cell membranes. CGP-12177A binding affinity was also determined in rat cerebral cortex membranes, where various alpha(1)-adrenoceptor subtypes are present. By means of [(3)H]prazosin binding competition experiments, we found that CGP-12177A bound to alpha(1D)-adrenoceptor-expressing BHK-21 cell membranes, with a binding affinity (pK(i)=5.39+/-0.27) almost identical to that measured in cerebral membranes (pK(i)=5.44+/-0.07), indicating that it is a non-subtype selective alpha(1)-adrenoceptor ligand. Moreover, CGP-12177A binding affinity was very close to its functional affinity evaluated in rat aorta in terms of antagonist potency against phenylephrine-induced contraction (pK(B)=5.65+/-0.07). In conclusion, our results demonstrate that, in order to evaluate CGP-12177A binding affinity at aorta and mesenteric artery alpha(1)-adrenoceptors, estimates in rat cerebral membranes are as reliable as those in recombinant rat alpha(1D)-adrenoceptors, since both values are very close to CGP-12177A functional affinities in isolated vessels.
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Jackson WF, Boerman EM, Lange EJ, Lundback SS, Cohen KD. Smooth muscle alpha1D-adrenoceptors mediate phenylephrine-induced vasoconstriction and increases in endothelial cell Ca2+ in hamster cremaster arterioles. Br J Pharmacol 2008; 155:514-24. [PMID: 18604236 DOI: 10.1038/bjp.2008.276] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND AND PURPOSE alpha(1)-Adrenoceptor agonists induce Ca(2+)-transients in endothelial cells (ECs) of arterioles. However, the presence of alpha(1)-adrenoceptors on arteriolar ECs has not been excluded, and the identity of alpha(1)-adrenoceptor subtypes in arterioles only has been inferred from pharmacology. Therefore, we determined which subtypes were expressed by vascular smooth muscle cells (VSMCs) and ECs, and which subtype mediated alpha(1)-adrenoceptor-induced constriction. EXPERIMENTAL APPROACH EC Ca(2+)-transients in isolated, cannulated hamster cremasteric arterioles or freshly isolated ECs were studied using Fura 2. Arteriolar diameter was measured by video microscopy. alpha(1)-Adrenoceptor expression was assessed by western blot of whole-arteriolar homogenates and real-time RT-PCR on enzymatically isolated VSMCs and ECs. KEY RESULTS Phenylephrine-induced constriction and EC Ca(2+)-transients were abolished by the alpha(1)-adrenoceptor antagonist prazosin (30 nM) in arterioles. Phenylephrine-induced constriction was inhibited by the alpha(1D)-adrenoceptor antagonist BMY 7378 (K(B)=2.96 nM) and the alpha(1A)-adrenoceptor antagonist 5-methylurapidil (K(B)=4.08 nM), suggesting a significant role for alpha(1D)-adrenoceptors. Western blots confirmed alpha(1D)-adrenoceptor expression, but did not detect alpha(1A)-adrenoceptors. VSMCs expressed alpha(1D)- and alpha(1A)-, but not alpha(1B)-, adrenoceptor transcripts. No alpha(1)-adrenoceptor transcripts were detected in ECs. Neither phenylephrine (10 microM) nor noradrenaline (0.1-1 microM) elicited Ca(2+)-transients in freshly isolated ECs, whereas the endothelium-dependent vasodilators methacholine (1 microM) and substance P (100 nM) consistently increased Ca(2+). CONCLUSIONS AND IMPLICATIONS We reject the hypothesis that hamster cremasteric arteriolar ECs express alpha(1)-adrenoceptors and conclude that alpha(1)-adrenoceptor agonists predominantly act on VSMC alpha(1D)-adrenoceptors to cause vasoconstriction and a subsequent rise in EC Ca(2+).
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Affiliation(s)
- W F Jackson
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI 48824, USA.
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Armenia A, Sattar MA, Abdullah NA, Khan MAH, Johns EJ. Functional subtypes of renal alpha1-adrenoceptor in diabetic and non-diabetic 2K1C Goldblatt renovascular hypertension. Acta Pharmacol Sin 2008; 29:564-72. [PMID: 18430364 DOI: 10.1111/j.1745-7254.2008.00788.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
AIM This study investigates the subtypes of the alpha1-adrenoceptor mediating the adrenergically-induced renal vasoconstrictor responses in streptozotocin-induced diabetic and non-diabetic 2-kidney one clip (2K1C) Goldblatt hypertensive rats. METHODS The renal blood flow responses to renal nerve stimulation, noradrenaline, phenylephrine, and methoxamine were measured in the absence and presence of nitrendipine, 5-methylurapidil, chloroethylclonidine and BMY 7378. RESULTS The renal vasoconstrictor responses were markedly attenuated by nitrendipine and 5- methylurapidil in the diabetic rats (all P< 0.05). In the non-diabetic rats, these responses were markedly attenuated by nitrendipine, 5-methylurapidil, and BMY 7378 (all P< 0.05). In both experimental groups, chloroethylclonidine markedly accentuated the renal vasoconstrictions caused by all the adrenergic stimuli (all P< 0.05). CONCLUSION These observations indicate that alpha 1A-adrenoceptor subtypes play a major role in mediating adrenergically-induced renal vasoconstriction in the diabetic 2K1C Goldblatt hypertensive rats. In the non-diabetic 2K1C Goldblatt hypertensive rats, contributions of alpha 1A and alpha 1D-adrenoceptor subtypes were proposed. Apart from post-synaptic alpha 1-adrenoceptors, both in the diabetic and non-diabetic 2K1C Goldblatt hypertensive rats, the potential involvement of presynaptic alpha 1- adrenoceptors is also suggested.
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Affiliation(s)
- A Armenia
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang 11800, Malaysia
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18
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Khan MAH, Sattar MA, Abdullah NA, Johns EJ. Alpha1B-adrenoceptors mediate adrenergically-induced renal vasoconstrictions in rats with renal impairment. Acta Pharmacol Sin 2008; 29:193-203. [PMID: 18215348 DOI: 10.1111/j.1745-7254.2008.00727.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
AIM This study examined whether alpha1B-adrenoceptors are involved in mediating adrenergically-induced renal vasoconstrictor responses in rats with pathophysiological and normal physiological states. METHODS Male Wistar Kyoto and spontaneously hypertensive rats were induced with acute renal failure or experimental early diabetic nephropathy by cisplatin or streptozotocin, respectively. Cisplatin-induced renal failure was confirmed by impaired renal function and pronounced tubular damage. Experimental early diabetic nephropathy was confirmed by hyperglycemia, changes in physiological parameters, and renal function. The hemodynamic study was conducted on anesthetized rats after 7 d of cisplatin (renal failure) and 4 weeks of streptozotocin (experimental early diabetic nephropathy). RESULTS In the rats with renal failure and experimental early diabetic nephropathy, there were marked reductions in their baseline renal blood flow (P<0.01). The baseline mean arterial blood pressure was either unaltered or lower (all P>0.05) in the renal failure and experimental early diabetic nephropathy rats, respectively, as compared to their non-renal failure and non-diabetic nephropathy controls. In the rats with renal impairment, chloroethylclonidine caused either accentuation or attenuation (all P<0.01) of the renal vasoconstrictor responses elicited by the adrenergic stimuli. However, in the non-renal failure and in the non-diabetic nephropathy rats, chloroethylclonidine did not cause any alteration in such responses (P>0.05). CONCLUSION This study demonstrated the presence of functional alpha1B-adrenoceptors that mediated the adrenergically-induced renal vasoconstrictions in rats with renal impairment, but not in rats with normal renal function.
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Affiliation(s)
- Md Abdul Hye Khan
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia.
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Lecoq JPH, Joris JL, Nelissen XP, Lamy ML, Heymans OY. Effect of adrenergic stimulation on cutaneous microcirculation immediately after surgical adventitiectomy in a rat skin flap model. Microsurgery 2008; 28:480-6. [DOI: 10.1002/micr.20528] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Hye Khan MA, Abdul Sattar M, Abdullah NA, Johns EJ. Cisplatin-induced nephrotoxicity causes altered renal hemodynamics in Wistar Kyoto and spontaneously hypertensive rats: Role of augmented renal alpha-adrenergic responsiveness. ACTA ACUST UNITED AC 2007; 59:253-60. [PMID: 17764917 DOI: 10.1016/j.etp.2007.05.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Accepted: 05/16/2007] [Indexed: 10/22/2022]
Abstract
The pathogenesis of cisplatin-induced renal failure is related to reduced renal blood flow due to severe tubular damage and enhanced renovascular resistance. It is also known that alpha(1)-adrenoceptors, the major subtype of alpha-adrenoceptors in renal vasculature play the pivotal role in regulating renal hemodynamics. With this background, we have hypothesized that the altered renal hemodynamics and enhanced renovascular resistance in cisplatin-induced renal failure might be caused by the altered alpha-adrenergic responsiveness with a possible involvement of alpha(1)-adrenoceptors in the renal vasculature. In a unique experimental approach with anesthetized rats, this study has therefore examined if there is any shift in the renovascular responsiveness to renal nerve stimulation and a series of alpha-adrenergic agonists in Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats with cisplatin-induced renal failure in comparison with their body weight-matched normal controls. Thirty-two male rats of both WKY (n=16) and SHR (n=16) origin with body weight 236+/-7.9 g received cisplatin (5mg/kg i.p.). The renal failure was confirmed in terms of significantly reduced renal blood flow, reduced creatinine clearance, increased fractional excretion of sodium, increased kidney index (all P<0.05) and tubular damage. After 7 days of cisplatin, the overnight fasted rats were anesthetized (sodium pentobarbitone, 60 mg/kg i.p.) and renal vasoconstrictor experiments were done. The changes in the vasoconstrictor responses were determined in terms of reductions in renal blood flow caused by electrical renal nerve stimulation or intrarenal administration of noradrenaline, phenylephrine and methoxamine. It was observed that in the cisplatin-treated renal failure WKY and SHR rats there were significant (all P<0.05) reductions in the renal blood flow along with significantly (P<0.05) higher renal adrenergic responsiveness as compared with their non-renal failure controls. The data showed that in the renal failure WKY and SHR rats, the altered renal hemodynamics might be caused by an augmented renal adrenergic responsiveness. The results obtained further led us to suggest that the augmented renal adrenergic responsiveness in the cisplatin-induced renal failure rats were possibly mediated by the alpha(1)-adrenoceptors.
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Affiliation(s)
- Md Abdul Hye Khan
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden, 11800 Penang, Malaysia
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Zacharia J, Hillier C, Tanoue A, Tsujimoto G, Daly CJ, McGrath JC, MacDonald A. Evidence for involvement of alpha1D-adrenoceptors in contraction of femoral resistance arteries using knockout mice. Br J Pharmacol 2006; 146:942-51. [PMID: 16170328 PMCID: PMC1751234 DOI: 10.1038/sj.bjp.0706395] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The role of alpha(1D)-adrenoceptors in vasoconstrictor responses to noradrenaline in mouse femoral resistance arteries was investigated using wire myography in alpha(1D)-adrenoceptor knockout (alpha(1D)-KO) and wild-type (WT) mice of the same genetic background.alpha(1D)-KO mice were 2.5-fold less sensitive than WTs to exogenous noradrenaline and BMY 7378 was significantly less potent against noradrenaline in alpha(1D)-KO mice than in WTs, showing a minor contribution of alpha(1D)-adrenoceptors in response to noradrenaline. Prazosin and 5-methyl-urapidil were equally effective against noradrenaline in alpha(1D)-KO and WT mice. Chloroethylclonidine produced a significantly greater attenuation of the response to noradrenaline in alpha(1D)-KO mice than in WTs. Responses to electrical field stimulation (EFS), at 2-20 Hz for 10 s and 0.09 ms pulse width were significantly smaller overall in alpha(1D)-KOs than in WTs although no significant differences were seen at the different frequencies.BMY 7378 produced significantly greater inhibition of responses at 2 and 5 Hz than at higher frequencies in WTs. In alpha(1D)-KOs, this greater sensitivity to BMY 7378 at lower frequencies was not apparent, confirming that the effect of BMY 7378 was due to blockade of alpha(1D)-adrenoceptors. Prazosin and 5-methyl-urapidil had similar inhibitory effects on responses to EFS in alpha(1D)-KO and WT mice. Chloroethylclonidine inhibited responses to EFS to a significantly greater extent in alpha(1D)-KO mice. The present study with alpha(1D)-KO mice shows that alpha(1D)-adrenoceptors contribute to vasoconstrictor responses to exogenous and neurally released noradrenaline in femoral resistance arteries.
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Affiliation(s)
- Joseph Zacharia
- Vascular Biology Group, Department of Biological & Biomedical Sciences, School of Life Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow G4 0BA, Scotland, UK
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Pérez-Rivera AA, Fink GD, Galligan JJ. Alpha-1B adrenoceptors mediate neurogenic constriction in mesenteric arteries of normotensive and DOCA-salt hypertensive mice. Auton Neurosci 2005; 121:64-73. [PMID: 16095979 DOI: 10.1016/j.autneu.2005.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2005] [Revised: 06/29/2005] [Accepted: 07/09/2005] [Indexed: 11/18/2022]
Abstract
The contribution of alpha-1 adrenergic receptor (alpha1-AR) subtypes to neurogenic constrictions of mesenteric resistance arteries from SHAM and deoxycorticosterone acetate-salt (DOCA-salt) hypertensive mice was assessed. Frequency-response curves (0.5-30 Hz) for transmural stimulation-evoked contractions were examined in SHAM and DOCA-salt arteries in vitro in the absence (control) and presence of prazosin (0.1 microM), PPADS (10 microM), yohimbine (1 microM), 5-methylurapidil (5-MU; 0.1 microM), L-765,314 (1 microM) and BMY-7378 (0.3 microM); selective antagonists at alpha1-, P2X, alpha2-, alpha1A-, alpha1B-, and alpha1D-AR, respectively. In SHAM arteries, prazosin but not PPADS inhibited neurogenic responses. L-765,314 substantially inhibited neurogenic responses while 5-MU had a small inhibitory effect. BMY-7378 did not alter contractile responses at all. In DOCA-salt arteries, prazosin reduced neurogenic responses with no further significant inhibition seen with PPADS. L-765,314 antagonized neurogenic constrictions to a level similar to that seen in SHAM arteries. Furthermore, 5-MU and BMY-7378 did not affect these responses. The density of noradrenergic nerves (assessed using glyoxylic acid-induced fluorescence) or norepinephrine (NE) content was not altered by DOCA-salt hypertension. These results indicate that NE is the primary mediator of neurogenic constriction of murine mesenteric arteries. Nerve-released NE acts primarily at alpha1B-and to a lesser extent at alpha1A-ARs in SHAM arteries whereas NE mediates neurogenic constrictions in DOCA-salt arteries by acting at alpha1B-ARs.
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Affiliation(s)
- Alex A Pérez-Rivera
- Department of Pharmacology and Toxicology, Michigan State University, B 328 Life Sciences Building, East Lansing, MI 48824, USA.
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Brahmadevara N, Shaw AM, MacDonald A. ALpha1-adrenoceptor antagonist properties of CGP 12177A and other beta-adrenoceptor ligands: evidence against beta(3)- or atypical beta-adrenoceptors in rat aorta. Br J Pharmacol 2005; 142:781-7. [PMID: 15205310 PMCID: PMC1575050 DOI: 10.1038/sj.bjp.0705840] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. The alpha(1)-adrenoceptor antagonist properties of the beta-adrenoceptor nonconventional partial agonist, CGP 12177A, was investigated in functional assays in rat aorta and in radioligand binding assays in rat cerebral cortical membranes. In addition, binding affinities of other beta-adrenoceptor ligands were measured to investigate any correlation between alpha(1)-adrenoceptor affinity and relaxant potency in phenylephrine-constricted rings. 2. In functional studies, CGP 12177A produced parallel rightward shifts of the phenylephrine CRC with no reduction in the maximum responses. Schild regression analysis gave a straight line with a slope of 0.95 (95% CL: 0.87-1.04), suggesting reversible competitive antagonism, and gave a pK(B) value of 5.26. In contrast, CGP 12177A (<or=300 microm) had no effect on contraction induced by the thromboxane-mimetic, U46619. 3. In binding studies, CGP 12177A competed monophasically with [(3)H]prazosin binding (Hill slope, 0.95, 95% CL: 0.76-1.13), giving a pK(i) value of 5.48, in good agreement with the pK(B) from functional studies. 4. Competition experiments with various other beta-adrenoceptor ligands showed that they all displaced [(3)H]prazosin in a manner consistent with one-site competition. pK(i) values were as follows: SR 59230A, 6.25; cyanopindolol, 6.33; bupranolol, 6.35; alprenolol, 5.90; propranolol, 5.80; BRL 37344, 5.50; ICI 118551, 5.55; CGP 20712A, 5.26. The pK(i) values correlated well with the pEC(50) values for relaxation of phenylephrine-constricted rat aorta obtained previously (r(2)=0.984, P<0.0001). 5. In conclusion, relaxant effects of CGP 12177A and other beta-adrenoceptor ligands in phenylephrine-constricted rat aorta can be attributed to alpha(1)-adrenoceptor blockade and are unrelated to effects at beta(3)-adrenoceptors or atypical beta-adrenoceptors.
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MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- Adrenergic alpha-1 Receptor Antagonists
- Adrenergic beta-Antagonists/administration & dosage
- Adrenergic beta-Antagonists/pharmacokinetics
- Alprenolol/pharmacology
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/pathology
- Aorta, Thoracic/physiology
- Binding Sites/drug effects
- Bupranolol/pharmacology
- Cell Membrane/drug effects
- Cell Membrane/metabolism
- Cerebral Cortex/drug effects
- Cerebral Cortex/metabolism
- Cerebral Cortex/pathology
- Dose-Response Relationship, Drug
- Ethanolamines/pharmacology
- Imidazoles/pharmacology
- Male
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Phenylephrine/administration & dosage
- Phenylephrine/antagonists & inhibitors
- Phenylephrine/pharmacokinetics
- Pindolol/analogs & derivatives
- Pindolol/pharmacology
- Prazosin/administration & dosage
- Prazosin/pharmacokinetics
- Propanolamines/administration & dosage
- Propanolamines/pharmacokinetics
- Propanolamines/pharmacology
- Propranolol/pharmacology
- Radioligand Assay/methods
- Rats
- Rats, Wistar
- Receptors, Adrenergic, alpha-1/physiology
- Receptors, Adrenergic, beta-3/drug effects
- Receptors, Adrenergic, beta-3/physiology
- Tritium
- United Kingdom
- Vasoconstriction/drug effects
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Affiliation(s)
- Nataraj Brahmadevara
- Department of Biological and Biomedical Sciences, School of Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, U.K
| | - Angus M Shaw
- Department of Biological and Biomedical Sciences, School of Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, U.K
| | - Allan MacDonald
- Department of Biological and Biomedical Sciences, School of Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, U.K
- Author for correspondence:
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Hosoda C, Koshimizu TA, Tanoue A, Nasa Y, Oikawa R, Tomabechi T, Fukuda S, Shinoura H, Oshikawa S, Takeo S, Kitamura T, Cotecchia S, Tsujimoto G. Two alpha1-adrenergic receptor subtypes regulating the vasopressor response have differential roles in blood pressure regulation. Mol Pharmacol 2004; 67:912-22. [PMID: 15598970 DOI: 10.1124/mol.104.007500] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To study the functional role of individual alpha1-adrenergic (AR) subtypes in blood pressure (BP) regulation, we used mice lacking the alpha1B-AR and/or alpha1D-AR with the same genetic background and further studied their hemodynamic and vasoconstrictive responses. Both the alpha1D-AR knockout and alpha1B-/alpha1D-AR double knockout mice, but not the alpha1B-AR knockout mice, had significantly (p < 0.05) lower levels of basal systolic and mean arterial BP than wild-type mice in nonanesthetized condition, and they showed no significant change in heart rate or in cardiac function, as assessed by echocardiogram. All mutants showed a significantly (p < 0.05) reduced catecholamine-induced pressor and vasoconstriction responses. It is noteworthy that the infusion of norepinephrine did not elicit any pressor response at all in alpha1B-/alpha1D-AR double knockout mice. In an attempt to further examine alpha1-AR subtype, which is involved in the genesis or maintenance of hypertension, BP after salt loading was monitored by tail-cuff readings and confirmed at the endpoint by direct intra-arterial recording. After salt loading, alpha1B-AR knockout mice developed a comparable level of hypertension to wild-type mice, whereas mice lacking alpha1D-AR had significantly (p < 0.05) attenuated BP and lower levels of circulating catecholamines. Our data indicated that alpha1B- and alpha1D-AR subtypes participate cooperatively in BP regulation; however, the deletion of the functional alpha1D-AR, not alpha1B-AR, leads to an antihypertensive effect. The study shows differential contributions of alpha1B- and alpha1D-ARs in BP regulation.
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MESH Headings
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/physiology
- Blood Pressure/drug effects
- Blood Pressure/physiology
- Cloning, Molecular
- Heart Rate/drug effects
- Heart Rate/physiology
- In Vitro Techniques
- Mice
- Mice, Knockout
- Potassium Chloride/pharmacology
- Prazosin/pharmacokinetics
- Radioligand Assay
- Receptors, Adrenergic, alpha-1/deficiency
- Receptors, Adrenergic, alpha-1/drug effects
- Receptors, Adrenergic, alpha-1/genetics
- Receptors, Adrenergic, alpha-1/physiology
- Recombinant Proteins/drug effects
- Recombinant Proteins/metabolism
- Vasoconstriction/drug effects
- Vasoconstriction/physiology
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Affiliation(s)
- Chihiro Hosoda
- Department of Genomic Drug Discovery Science, Graduate School of Pharmaceutical Sciences, Kyoto University Faculty of Pharmaceutical Sciences, Kyoto University, Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
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Zacharia J, Hillier C, Macdonald A. Pharmacological characterization of α1-adrenoceptors in mouse isolated femoral small arteries. Eur J Pharmacol 2004; 503:155-63. [PMID: 15496310 DOI: 10.1016/j.ejphar.2004.09.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2004] [Revised: 09/06/2004] [Accepted: 09/10/2004] [Indexed: 11/19/2022]
Abstract
Arteries were isolated from male DBA/2 mice and mounted on a small vessel wire myograph for isometric recording. Responses to exogenous noradrenaline were inhibited with high affinity by prazosin (pKB, 9.3) and 5-methyl-urapidil (pKB, 9.2) and with low affinity by 8-[2-[4-(2-methoxyphenyl)-1 piperazinyl]ethyl]-8-azaspiro[4.5]decane-7,9-dione (BMY 7378) (pA(2), 6.7). Chloroethylclonidine (10 microM) produced only a small reduction in the maximum response to noradrenaline. Responses to electrical field stimulation were also inhibited with high affinity by prazosin (pIC50, 9.3-9.5) and 5-methyl-urapidil (pIC50, 8.0-8.3). Responses were sensitive to BMY 7378 at low frequencies of stimulation (pIC50 at 2 Hz, 8.2) but not at high frequencies (pIC50 at 20 Hz, 6.5). In conclusion, contractions to exogenous and endogenous noradrenaline in mouse femoral small arteries are mediated mainly by alpha1A-adrenoceptors. alpha1D-adrenoceptors are not involved in responses to exogenous noradrenaline but appear to be activated by neurally released noradrenaline at a low frequency of stimulation.
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Affiliation(s)
- Joseph Zacharia
- Department of Biological and Biomedical Sciences, School of Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, Scotland, UK
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