title: The properties of spontaneous transient inward currents of interstitial cells in rabbit portal vein.
abstract: The present study was designed to investigate the properties of spontaneous transient inward currents generated by interstitial cells (ICs) in the rabbit portal vein. Single ICs were freshly isolated from smooth muscle of the rabbit portal vein enzymetically. Using whole-cell patch clamp techniques, the spontaneous transient inward currents (STICs) were recorded at -60 mV of holding potential in freshly dispersed ICs. Both gadolinium, a non-selective cation channel inhibitor, and niflumic acid, a calcium-activated chloride channel blocker, abolished the inward currents. Replacement of external Na(+) with N-methyl-d-glucamine (NMDG(+)) also blocked the inward currents. The inward currents were abolished by caffeine, carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP), thapsigargin and ryanodine, but were partly inhibited by 2-aminoethoxydiphenyl borate (2-APB). W-7, a calmodulin inhibitor, increased the amplitude of the inward currents. These results suggest that non-selective cation channels are involved in the generation of the spontaneous transient inward currents recorded from ICs. The currents are regulated by intracellular calcium and calmodulin. But in the present study, the involvement of the calcium-activated chloride channels in the generation of the currents cannot be excluded.
authors.affiliation: Department of Physiology, School of Medicine, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Huang
authors.forename: Dan
authors.initials: D
authors.lastname: Zhao
authors.forename: Zuo-Yu
authors.initials: ZY
authors.lastname: Wang
authors.forename: Ming-Liang
authors.initials: ML
authors.lastname: Zhang
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Yan
authors.forename: Yan-Fei
authors.initials: YF
authors.lastname: Han
authors.forename: Wen-Xie
authors.initials: WX
authors.lastname: Xu
authors.forename: Zong-Lai
authors.initials: ZL
authors.lastname: Jiang
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002147:Calmodulin / Q000494:pharmacology; D002478:Cells, Cultured; D005260:Female; D005682:Gadolinium / Q000494:pharmacology; D005971:Glutamates / Q000494:pharmacology; D056885:Interstitial Cells of Cajal / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000502:physiology*; D009544:Niflumic Acid / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D011169:Portal Vein / Q000166:cytology / Q000502:physiology*; D011817:Rabbits; D050051:Transient Receptor Potential Channels / Q000378:metabolism
chemical_list: D002147:Calmodulin; D005971:Glutamates; D050051:Transient Receptor Potential Channels; C014574:gamma-glutamylmethylamide; D009544:Niflumic Acid; D005682:Gadolinium; D002118:Calcium