title: Role of gap junctions in the contractile response to agonists in the mesenteric artery of spontaneously hypertensive rats.
abstract: To investigate the effects of hypertension on the changes in gap junctions between vascular smooth muscle cells (VSMCs) in the mesenteric artery (MA) of spontaneously hypertensive rats (SHRs). Whole-cell patch clamp, pressure myography, real-time quantitative reverse transcription PCR (qRT-PCR), western blot analysis and transmission electron microscopy were used to examine the differences in expression and function of the gap junction between MA VSMCs of SHR and control normotensive Wistar-Kyoto (WKY) rats. (1) Whole-cell patch clamp measurements showed that the membrane capacitance and conductance of in-situ MA VSMCs of SHR were significantly greater than those of WKY rats (P<0.05), suggesting enhanced gap junction coupling between MA VSMCs of SHR. (2) The administration of phenylephrine (PE) and KCl (an endothelium-independent vasoconstrictor) initiated more pronounced vasoconstriction in SHR versus WKY rats (P<0.05). Furthermore, 2-APB (a gap junction inhibitor) attenuated PE- and KCl-induced vasoconstriction, and the inhibitory effects of 2-APB were significantly greater in SHR (P<0.05). (3) The expression of connexin 45 (Cx45) mRNA and protein in the MA was greater in SHR versus WKY rats (P<0.05). The level of phosphorylated Cx43 was significantly higher in SHR versus WKY rats (P<0.05), although the expression of total Cx43 mRNA and protein in the MA was equivalent between SHR and WKY rats. Electron microscopy revealed that the gap junctions were significantly larger in SHR versus WKY rats. Increases in the expression of Cx45 and phosphorylation of Cx43 may contribute to the enhancement of communication across gap junctions between MA VSMCs of SHR, which may increase the contractile response to agonists.
authors.affiliation: 1] Department of Physiology, Medical College of Shihezi University, Shihezi, PR China [2] The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, PR China.
authors.forename: Ke-Tao
authors.initials: KT
authors.lastname: Ma
authors.affiliation: 1] The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, PR China [2] Department of Pathophysiology, Medical College of Shihezi University, Shihezi, PR China.
authors.forename: Xin-Zhi
authors.initials: XZ
authors.lastname: Li
authors.affiliation: 1] Department of Physiology, Medical College of Shihezi University, Shihezi, PR China [2] The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Physiology, Medical College of Shihezi University, Shihezi, PR China.
authors.forename: Xue-Wei
authors.initials: XW
authors.lastname: Jiang
authors.affiliation: Department of Physiology, Medical College of Shihezi University, Shihezi, PR China.
authors.forename: Xin-Yan
authors.initials: XY
authors.lastname: Chen
authors.affiliation: Department of Physiology, Medical College of Shihezi University, Shihezi, PR China.
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Liu
authors.affiliation: 1] Department of Physiology, Medical College of Shihezi University, Shihezi, PR China [2] The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhao
authors.affiliation: 1] Department of Physiology, Medical College of Shihezi University, Shihezi, PR China [2] The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, PR China.
authors.forename: Zhong-Shuang
authors.initials: ZS
authors.lastname: Zhang
authors.affiliation: 1] Department of Physiology, Medical College of Shihezi University, Shihezi, PR China [2] The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, PR China.
authors.forename: Jun-Qiang
authors.initials: JQ
authors.lastname: Si
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001835:Body Weight / Q000502:physiology; D018031:Connexin 43 / Q000096:biosynthesis; D017629:Gap Junctions / Q000502:physiology* / Q000648:ultrastructure; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000648:ultrastructure; D009213:Myography; D018408:Patch-Clamp Techniques; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D060888:Real-Time Polymerase Chain Reaction; D014661:Vasoconstriction / Q000187:drug effects
chemical_list: D018031:Connexin 43; D012333:RNA, Messenger