title: Calcium influx and release mechanism(s) in histamine-induced myometrial contraction in buffaloes.
abstract: The present study was undertaken to characterize the presence of histamine H1R using molecular biology tools and unravel the influx and release mechanism(s) involved in calcium signalling cascades in histamine-induced myometrial contraction in buffaloes. The presence of H1R mRNA transcript and immunoreactive membrane protein in buffalo myometrium was confirmed by RT-PCR and Western blot analysis. Further, histamine produced concentration-dependent (1nM-10μM) contraction in buffalo myometrium with a potency of 7.13±0.11. When myometrial strips were pre-incubated either with Ca(2+) free solution or with nifedipine, a L-type Ca(2+) channel blocker, dose response curve (DRC) of histamine was significantly (P<0.05) shifted towards right with decline in maximal contraction (Emax). Reduction in Emax of histamine in the presence of nifedipine (55.75±3.10%) was significantly (P<0.001) greater than that in the presence of ruthenium red (93.61±3.43%), a blocker of IP3-gated and RyR-sensitive Ca(2+) channels. Moreover, histamine produced only 26.87±1.99% of the maximum contraction in the presence of both nifedipine and CPA (blocker of sarco-endoplasmic reticulum Ca(2+)-ATPase). Interestingly, following concurrent exposure to U-73122 (a PL-C inhibitor) and nifedipine, the DRC of histamine was significantly (P<0.05) shifted towards left with increase in maximal contraction (126.30±3.36%). Our findings in buffalo uterus thus suggest that influx of extracellular calcium plays a major role in histamine-induced myometrial contraction, while release of intracellular calcium through calcium-release channels of sarcoplasmic reticulum has a minor role. A possible involvement of non-selective cation channels in histamine-induced myometrial contraction cannot be ruled out, and therefore requires further investigations.
authors.affiliation: Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura 281001, India.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Sharma
authors.affiliation: Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura 281001, India.
authors.forename: Soumen
authors.initials: S
authors.lastname: Choudhury
authors.affiliation: Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura 281001, India.
authors.forename: Udayraj P
authors.initials: UP
authors.lastname: Nakade
authors.affiliation: Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura 281001, India.
authors.forename: Rajkumar Singh
authors.initials: RS
authors.lastname: Yadav
authors.affiliation: Department of Pharmacology & Toxicology, College of Veterinary Science and Animal Husbandry, U.P. Pandit Deen Dayal Upadhyaya Pashu Chikitsa Vigyan Vishwavidyalaya Evam Go-Anusandhan Sansthan, Mathura 281001, India. Electronic address: profsatish@gmail.com.
authors.forename: Satish Kumar
authors.initials: SK
authors.lastname: Garg
mesh_terms: D000818:Animals; D002020:Buffaloes; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000494:pharmacology; D004963:Estrenes / Q000008:administration & dosage / Q000494:pharmacology; D005260:Female; D006632:Histamine / Q000494:pharmacology*; D009543:Nifedipine / Q000008:administration & dosage / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology; D011760:Pyrrolidinones / Q000008:administration & dosage / Q000494:pharmacology; D012430:Ruthenium Red; D013194:Staining and Labeling; D046509:Tissue Culture Techniques / Q000662:veterinary; D014590:Uterine Contraction / Q000187:drug effects*
chemical_list: D002121:Calcium Channel Blockers; D004963:Estrenes; D010726:Phosphodiesterase Inhibitors; D011760:Pyrrolidinones; D012430:Ruthenium Red; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D006632:Histamine; D009543:Nifedipine; D002118:Calcium
keywords: Buffalo; Calcium; Histamine; Myometrium