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Wang H, Jing R, Trexler C, Li Y, Tang H, Pan Z, Zhu S, Zhao B, Fang X, Liu J, Chen J, Ouyang K. Deletion of IP 3R1 by Pdgfrb-Cre in mice results in intestinal pseudo-obstruction and lethality. J Gastroenterol 2019; 54:407-418. [PMID: 30382364 PMCID: PMC8109192 DOI: 10.1007/s00535-018-1522-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Accepted: 10/17/2018] [Indexed: 02/04/2023]
Abstract
BACKGROUND Inositol 1,4,5-trisphosphate receptors (IP3Rs) are a family of intracellular Ca2+ release channels located on the membrane of endoplasmic reticulum, which have been shown to play critical roles in various cellular and physiological functions. However, their function in regulating gastrointestinal (GI) tract motility in vivo remains unknown. Here, we investigated the physiological function of IP3R1 in the GI tract using genetically engineered mouse models. METHODS Pdgfrb-Cre mice were bred with homozygous Itpr1 floxed (Itpr1f/f) mice to generate conditional IP3R1 knockout (pcR1KO) mice. Cell lineage tracing was used to determine where Pdgfrb-Cre-mediated gene deletion occurred in the GI tract. Isometric tension recording was used to measure the effects of IP3R1 deletion on muscle contraction. RESULTS In the mouse GI tract, Itpr1 gene deletion by Pdgfrb-Cre occurred in smooth muscle cells, enteric neurons, and interstitial cells of Cajal. pcR1KO mice developed impaired GI motility, with prolonged whole-gut transit time and abdominal distention. pcR1KO mice also exhibited lethality as early as 8 weeks of age and 50% of pcR1KO mice were dead by 40 weeks after birth. The frequency of spontaneous contractions in colonic circular muscles was dramatically decreased and the amplitude of spontaneous contractions was increased in pcR1KO mice. Deletion of IP3R1 in the GI tract also reduced the contractile response to the muscarinic agonist, carbachol, as well as to electrical field stimulation. However, KCl-induced contraction and expression of smooth muscle-specific contractile genes were not significantly altered in pcR1KO mice. CONCLUSIONS Here, we provided a novel mouse model for impaired GI motility and demonstrated that IP3R1 plays a critical role in regulating physiological function of GI tract in vivo.
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Affiliation(s)
- Hong Wang
- Drug Discovery Center, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Ran Jing
- Xiangya Hospital, Central South University, Changsha 410011, China
| | - Christa Trexler
- Department of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Yali Li
- Drug Discovery Center, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Huayuan Tang
- Drug Discovery Center, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Zhixiang Pan
- Drug Discovery Center, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Siting Zhu
- Drug Discovery Center, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Beili Zhao
- Drug Discovery Center, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Xi Fang
- Department of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Jie Liu
- Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Ju Chen
- Department of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Kunfu Ouyang
- Drug Discovery Center, State Key Laboratory of Chemical Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China
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Intracellular emetic signaling cascades by which the selective neurokinin type 1 receptor (NK 1R) agonist GR73632 evokes vomiting in the least shrew (Cryptotis parva). Neurochem Int 2018; 122:106-119. [PMID: 30453005 DOI: 10.1016/j.neuint.2018.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 11/14/2018] [Accepted: 11/15/2018] [Indexed: 12/26/2022]
Abstract
To characterize mechanisms involved in neurokinin type 1 receptor (NK1R)-mediated emesis, we investigated the brainstem emetic signaling pathways following treating least shrews with the selective NK1R agonist GR73632. In addition to episodes of vomiting over a 30-min observation period, a significant increase in substance P-immunoreactivity in the emetic brainstem dorsal motor nucleus of the vagus (DMNX) occurred at 15 min post an intraperitoneal (i.p.) injection GR73632 (5 mg/kg). In addition, time-dependent upregulation of phosphorylation of several emesis -associated protein kinases occurred in the brainstem. In fact, Western blots demonstrated significant phosphorylations of Ca2+/calmodulin kinase IIα (CaMKIIα), extracellular signal-regulated protein kinase1/2 (ERK1/2), protein kinase B (Akt) as well as α and βII isoforms of protein kinase C (PKCα/βII). Moreover, enhanced phospho-ERK1/2 immunoreactivity was also observed in both brainstem slices containing the dorsal vagal complex emetic nuclei as well as in jejunal sections from the shrew small intestine. Furthermore, our behavioral findings demonstrated that the following agents suppressed vomiting evoked by GR73632 in a dose-dependent manner: i) the NK1R antagonist netupitant (i.p.); ii) the L-type Ca2+ channel (LTCC) antagonist nifedipine (subcutaneous, s.c.); iii) the inositol trisphosphate receptor (IP3R) antagonist 2-APB (i.p.); iv) store-operated Ca2+ entry inhibitors YM-58483 and MRS-1845, (i.p.); v) the ERK1/2 pathway inhibitor U0126 (i.p.); vi) the PKC inhibitor GF109203X (i.p.); and vii) the inhibitor of phosphatidylinositol 3-kinase (PI3K)-Akt pathway LY294002 (i.p.). Moreover, NK1R, LTCC, and IP3R are required for GR73632-evoked CaMKIIα, ERK1/2, Akt and PKCα/βII phosphorylation. In addition, evoked ERK1/2 phosphorylation was sensitive to inhibitors of PKC and PI3K. These findings indicate that the LTCC/IP3R-dependent PI3K/PKCα/βII-ERK1/2 signaling pathways are involved in NK1R-mediated vomiting.
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Zhong W, Chebolu S, Darmani NA. Intracellular emetic signaling evoked by the L-type Ca 2+ channel agonist FPL64176 in the least shrew (Cryptotis parva). Eur J Pharmacol 2018; 834:157-168. [PMID: 29966616 DOI: 10.1016/j.ejphar.2018.06.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 06/09/2018] [Accepted: 06/28/2018] [Indexed: 12/20/2022]
Abstract
Ca2+ plays a major role in maintaining cellular homeostasis and regulates processes including apoptotic cell death and side-effects of cancer chemotherapy including vomiting. Currently we explored the emetic mechanisms of FPL64176, an L-type Ca2+ channel (LTCC) agonist with maximal emetogenic effect at its 10 mg/kg dose. FPL64176 evoked c-Fos immunoreactivity in shrew brainstem sections containing the vomit-associated nuclei, nucleus tractus solitarius (NTS) and dorsal motor nucleus of the vagus. FPL64176 also increased phosphorylation of proteins ERK1/2, PKCα/βII and Akt in the brainstem. Moreover, their corresponding inhibitors (PD98059, GF 109203X and LY294002, respectively) reduced FPL64176-evoked vomiting. A 30 min subcutaneous (s.c.) pretreatment with the LTCC antagonist nifedipine (10 mg/kg) abolished FPL64176-elicited vomiting, c-Fos expression, and emetic effector phosphorylation. Ryanodine receptors (RyRs) and inositol trisphosphate receptors (IP3Rs) mediate intracellular Ca2+ release from the sarcoplasmic/endoplasmic reticulum. The RyR antagonist dantrolene (i.p.), or a combination of low doses of nifedipine and dantrolene, but not the IP3R antagonist 2-APB, significantly attenuated FPL64176-induced vomiting. The serotonin type 3 receptor (5-HT3R) antagonist palonosetron (s.c.), the neurokinin 1 receptor (NK1R) antagonist netupitant (i.p.) or a combination of non-effective doses of netupitant and palonosetron showed antiemetic potential against FPL64176-evoked vomiting. Serotonin (5-HT) and substance P immunostaining revealed FPL64176-induced emesis was accompanied by an increase in 5-HT but not SP-immunoreactivity in the dorsomedial subdivision of the NTS. These findings demonstrate that Ca2+ mobilization through LTCCs and RyRs, and subsequent emetic effector phosphorylation and 5-HT release play important roles in FPL64176-induced emesis which can be prevented by 5-HT3R and NK1R antagonists.
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Affiliation(s)
- Weixia Zhong
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 E. Second Street, Pomona, CA 91766, United States
| | - Seetha Chebolu
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 E. Second Street, Pomona, CA 91766, United States
| | - Nissar A Darmani
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, 309 E. Second Street, Pomona, CA 91766, United States.
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Tang Q, Quan X, Yan L, Ren H, Chen W, Xia H, Luo H. Mechanism of sodium hydrosulfide modulation of L-type calcium channels in rat colonic smooth muscle cells. Eur J Pharmacol 2017; 818:356-363. [PMID: 29104047 DOI: 10.1016/j.ejphar.2017.11.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 10/24/2017] [Accepted: 11/01/2017] [Indexed: 02/07/2023]
Abstract
Hydrogen sulfide (H2S) can exert different effects on the gastrointestinal tract by modulating ion channels. Previously, we found that H2S donor sodium hydrosulfide (NaHS) regulates colonic motility through L-type calcium channels, but the molecular mechanism remains unknown. The present study was designed to investigate possible mechanisms underlying the modulation of L-type calcium channels by NaHS in rat colonic smooth muscle cells. L-type calcium currents in colonic smooth muscle cells were recorded using the whole-cell patch-clamp technique. Spontaneous contractions of mid-colonic smooth muscle strips were measured in an organ bath system and a biological signal acquisition system. NaHS evoked a significant rightward shift in the steady-state activation curve of L-type calcium channels, changed the shape of the current-voltage (I-V) curve, and decreased the peak current density at 0mV, although it significantly increased with higher stimulatory voltage. The sulfhydryl-modifying reagent DL-dithiothreitol (DTT) enhanced the effects of NaHS on L-type calcium channels, while diamide (DM) and reduced L-glutathione (GSH) alleviated the effects of NaHS. Additionally, NaHS inhibited the spontaneous high-amplitude contractions of both longitudinal and circular smooth muscle strips in a dose-dependent manner. The inhibitory effects were reversible. DTT and GSH enhanced the effects of NaHS, while DM attenuated the effects of NaHS. In conclusion, NaHS modulates L-type calcium channels in rat colonic smooth muscle cells and regulates the contractile activity of colonic smooth muscle, potentially by modifying the free sulfhydryl groups of L-type calcium channels.
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Affiliation(s)
- Qincai Tang
- Department of Gastroenterology, Renmin Hospital of Wuhan University, 430060 Wuhan, Hubei Province, China
| | - Xiaojing Quan
- Department of Gastroenterology, Shanghai General Hospital, Shanghai Jiao Tong University, 200080 Shanghai, China
| | - Lin Yan
- Department of Gastroenterology, Renmin Hospital of Wuhan University, 430060 Wuhan, Hubei Province, China
| | - Haixia Ren
- Department of Gastroenterology, Renmin Hospital of Wuhan University, 430060 Wuhan, Hubei Province, China
| | - Wei Chen
- Department of Gastroenterology, Renmin Hospital of Wuhan University, 430060 Wuhan, Hubei Province, China; Key Laboratory of Hubei Province for Digestive System Diseases, 430060 Wuhan, Hubei Province, China
| | - Hong Xia
- Department of Gastroenterology, Renmin Hospital of Wuhan University, 430060 Wuhan, Hubei Province, China; Key Laboratory of Hubei Province for Digestive System Diseases, 430060 Wuhan, Hubei Province, China
| | - Hesheng Luo
- Department of Gastroenterology, Renmin Hospital of Wuhan University, 430060 Wuhan, Hubei Province, China; Key Laboratory of Hubei Province for Digestive System Diseases, 430060 Wuhan, Hubei Province, China.
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Kim JH, Jung SM, Shin JG, Cheong HS, Seo JM, Kim DY, Oh JT, Kim HY, Jung K, Shin HD. Potential association between ITPKC genetic variations and Hirschsprung disease. Mol Biol Rep 2017; 44:307-313. [PMID: 28664405 DOI: 10.1007/s11033-017-4111-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 06/24/2017] [Indexed: 02/03/2023]
Abstract
Hirschsprung disease (HSCR) is a congenital and complex disorder characterized by intestinal obstruction due to the absence of enteric neurons along variable lengths of the hindgut. Our recent genome-wide association study (GWAS) has revealed regional associations with HSCR at several loci of inositol-trisphosphate 3-kinase C (ITPKC). For fine mapping, we additionally selected and genotyped a total of 12 single nucleotide polymorphisms (SNPs) of ITPKC in 187 HSCR patients and 283 unaffected controls, and performed a further combined imputation analysis based on genotype data from this second stage of fine mapping and our previous GWAS stage, totaling 902 subjects (187 HSCR cases and 715 controls). As a result, several SNPs (minimum P = 0.004) and a haplotype (P = 0.02) were found to be significantly associated with HSCR. In further in silico analyses to ascertain the potential functions of the significant variants, the change from the common allele to the rare allele of the highly conserved nonsynonymous rs76785336 showed a difference in mRNA folding structure. In the case of intronic SNPs, rs2607420 with a high consensus value was predicted to be a new splice site. Although this study has limitations (such as lack of functional evaluations, small number of cases, and further need of replication in other cohorts), our findings suggest that genetic variants of ITPKC may have a potential association with HSCR susceptibility and/or developmental diseases related to enteric nervous system development.
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Affiliation(s)
- Jeong-Hyun Kim
- Research Institute for Basic Science, Sogang University, Seoul, 04107, Republic of Korea
| | - Soo-Min Jung
- Department of Surgery, Konkuk University Medical Center, Seoul, 05030, Republic of Korea
| | - Joong-Gon Shin
- Department of Life Science, Sogang University, Seoul, 04107, Republic of Korea
| | - Hyun Sub Cheong
- Department of Genetic Epidemiology, SNP Genetics, Inc., Seoul, 04107, Republic of Korea
| | - Jeong-Meen Seo
- Division of Pediatric Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, 06351, Republic of Korea
| | - Dae-Yeon Kim
- Department of Pediatric Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, 05505, Republic of Korea
| | - Jung-Tak Oh
- Department of Pediatric Surgery, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Hyun-Young Kim
- Department of Pediatric Surgery, Seoul National University Children's Hospital, Seoul, 03080, Republic of Korea
| | - Kyuwhan Jung
- Department of Surgery, Jeju National University Hospital, Jeju, 63241, Republic of Korea
| | - Hyoung Doo Shin
- Research Institute for Basic Science, Sogang University, Seoul, 04107, Republic of Korea. .,Department of Life Science, Sogang University, Seoul, 04107, Republic of Korea.
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Zhong W, Picca AJ, Lee AS, Darmani NA. Ca2+ signaling and emesis: Recent progress and new perspectives. Auton Neurosci 2017; 202:18-27. [DOI: 10.1016/j.autneu.2016.07.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 07/21/2016] [Accepted: 07/22/2016] [Indexed: 02/07/2023]
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Zhong W, Chebolu S, Darmani NA. Thapsigargin-induced activation of Ca(2+)-CaMKII-ERK in brainstem contributes to substance P release and induction of emesis in the least shrew. Neuropharmacology 2015; 103:195-210. [PMID: 26631534 DOI: 10.1016/j.neuropharm.2015.11.023] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/06/2015] [Accepted: 11/23/2015] [Indexed: 11/29/2022]
Abstract
Cytoplasmic calcium (Ca(2+)) mobilization has been proposed to be an important factor in the induction of emesis. The selective sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase (SERCA) inhibitor thapsigargin, is known to deplete intracellular Ca(2+) stores, which consequently evokes extracellular Ca(2+) entry through cell membrane-associated channels, accompanied by a prominent rise in cytosolic Ca(2+). A pro-drug form of thapsigargin is currently under clinical trial as a targeted cancer chemotherapeutic. We envisioned that the intracellular effects of thapsigargin could cause emesis and planned to investigate its mechanisms of emetic action. Indeed, thapsigargin did induce vomiting in the least shrew in a dose-dependent and bell-shaped manner, with maximal efficacy (100%) at 0.5 mg/kg (i.p.). Thapsigargin (0.5 mg/kg) also caused increases in c-Fos immunoreactivity in the brainstem emetic nuclei including the area postrema (AP), nucleus tractus solitarius (NTS) and dorsal motor nucleus of the vagus (DMNX), as well as enhancement of substance P (SP) immunoreactivity in DMNX. In addition, thapsigargin (0.5 mg/kg, i.p.) led to vomit-associated and time-dependent increases in phosphorylation of Ca(2+)/calmodulin kinase IIα (CaMKIIα) and extracellular signal-regulated protein kinase 1/2 (ERK1/2) in the brainstem. We then explored the suppressive potential of diverse chemicals against thapsigargin-evoked emesis including antagonists of: i) neurokinin-1 receptors (netupitant), ii) the type 3 serotonin receptors (palonosetron), iii) store-operated Ca(2+) entry (YM-58483), iv) L-type Ca(2+) channels (nifedipine), and v) SER Ca(2+)-release channels inositol trisphosphate (IP3Rs) (2-APB)-, and ryanodine (RyRs) (dantrolene)-receptors. In addition, the antiemetic potential of inhibitors of CaMKII (KN93) and ERK1/2 (PD98059) were investigated. All tested antagonists/blockers attenuated emetic parameters to varying degrees except palonosetron, however a combination of non-effective doses of netupitant and palonosetron exhibited additive antiemetic efficacy. A low-dose combination of nifedipine and 2-APB plus dantrolene mixture completely abolished thapsigargin-evoked vomiting, CaMKII-ERK1/2 activation and SP elevation. In addition, pretreatment with KN93 or PD98059 suppressed thapsigargin-induced increases in SP and ERK1/2 activation. Intracerebroventricular injection of netupitant suppressed vomiting caused by thapsigargin which suggests that the principal site of evoked emesis is the brainstem. In sum, this is the first study to demonstrate that thapsigargin causes vomiting via the activation of the Ca(2+)-CaMKII-ERK1/2 cascade, which is associated with an increase in the brainstem tissue content of SP, and the evoked emesis occurs through SP-induced activation of neurokinin-1 receptors.
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Affiliation(s)
- Weixia Zhong
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona CA 91766, USA
| | - Seetha Chebolu
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona CA 91766, USA
| | - Nissar A Darmani
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona CA 91766, USA.
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Kawaguchi A, Sato M, Kimura M, Yamazaki T, Yamamoto H, Tazaki M, Ichinohe T, Shibukawa Y. Functional expression of bradykinin B1 and B2 receptors in neonatal rat trigeminal ganglion neurons. Front Cell Neurosci 2015; 9:229. [PMID: 26124706 PMCID: PMC4466439 DOI: 10.3389/fncel.2015.00229] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 06/01/2015] [Indexed: 01/03/2023] Open
Abstract
Bradykinin (BK) and its receptors (B1 and B2 receptors) play important roles in inflammatory nociception. However, the patterns of expression and physiological/pathological functions of B1 and B2 receptors in trigeminal ganglion (TG) neurons remain to be fully elucidated. We investigated the functional expression of BK receptors in rat TG neurons. We observed intense immunoreactivity of B2 receptors in TG neurons, while B1 receptors showed weak immunoreactivity. Expression of the B2 receptor colocalized with immunoreactivities against the pan-neuronal marker, neurofilament H, substance P, isolectin B4, and tropomyosin receptor kinase A antibodies. Both in the presence and absence of extracellular Ca2+ ([Ca2+]o), BK application increased the concentration of intracellular free Ca2+ ([Ca2+]i). The amplitudes of BK-induced [Ca2+]i increase in the absence of [Ca2+]o were significantly smaller than those in the presence of Ca2+. In the absence of [Ca2+]o, BK-induced [Ca2+]i increases were sensitive to B2 receptor antagonists, but not to a B1 receptor antagonist. However, B1 receptor agonist, Lys-[Des-Arg9]BK, transiently increased [Ca2+]i in primary cultured TG neurons, and these increases were sensitive to a B1 receptor antagonist in the presence of [Ca2+]o. These results indicated that B2 receptors were constitutively expressed and their activation induced the mobilization of [Ca2+]i from intracellular stores with partial Ca2+ influx by BK. Although constitutive B1 receptor expression could not be clearly observed immunohistochemically in the TG cryosection, cultured TG neurons functionally expressed B1 receptors, suggesting that both B1 and B2 receptors involve pathological and physiological nociceptive functions.
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Affiliation(s)
- Aya Kawaguchi
- Department of Dental Anesthesiology, Tokyo Dental College Tokyo, Japan
| | - Masaki Sato
- Department of Physiology, Tokyo Dental College Tokyo, Japan
| | - Maki Kimura
- Department of Physiology, Tokyo Dental College Tokyo, Japan
| | - Takaki Yamazaki
- Department of Histology and Developmental Biology, Tokyo Dental College Tokyo, Japan
| | - Hitoshi Yamamoto
- Department of Histology and Developmental Biology, Tokyo Dental College Tokyo, Japan
| | | | - Tatsuya Ichinohe
- Department of Dental Anesthesiology, Tokyo Dental College Tokyo, Japan
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The effect of bradykinin on the electrical activity of rat myenteric neurons. Eur J Pharmacol 2014; 738:158-69. [PMID: 24886885 DOI: 10.1016/j.ejphar.2014.05.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 04/01/2014] [Accepted: 05/10/2014] [Indexed: 01/21/2023]
Abstract
Bradykinin is a mediator involved in inflammatory processes in the gut. Here we investigated the effect of bradykinin on the electrical activity of rat myenteric neurons, the key players for regulation of gastrointestinal motility. Bradykinin (2 × 10(-8)mol/l) induced a biphasic increase in frequency of action potentials measured with microelectrode arrays. This increase was mirrored by a biphasic increase in cytosolic Ca(2+) concentration ([Ca(2+)]i), which was observed in about 40% of the myenteric neurons. The bradykinin B1 receptor agonist des-arg(9)-bradykinin as well as the bradykinin B2 receptor agonist hyp(3)-bradykinin induced a similar effect on [Ca(2+)]i. Immunocytochemical stainings confirmed the expression of both receptor types by myenteric ganglionic cells. Real time PCR showed that the inducible B1 receptor was upregulated during cell culture. The inhibition of cyclooxygenases with piroxicam reduced the effect of bradykinin on the electrical activity of myenteric neurons. The suppression of the glial growth on microelectrode arrays did not affect the bradykinin-induced change in frequency of action potentials. This suggests that prostaglandins, which probably mediate the effect of bradykinin, are not exclusively released from glial cells. The bradykinin-induced increase in [Ca(2+)]i was dependent on the presence of extracellular Ca(2+) and was inhibited by Co(2+), Cd(2+), and Ni(2+), blockers of voltage-dependent Ca(2+) channels, indicating a stimulation of the influx of extracellular Ca(2+) by the kinin. Consequently, bradykinin induces a Ca(2+) influx in myenteric neurons via Ca(2+) channels in the plasma membrane.
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