title: Bk(Ca) channel activity enhances with muscle stretch in guinea-pig urinary bladder smooth muscle.
abstract: Possible effects of muscle stretch on the spontaneous rhythmic contractile activity and the extent of contribution of voltage-dependent and Ca2+ -activated K+ (BK(Ca)) channels were examined mechanically in guinea-pig urinary bladder smooth muscle (UBSM). The amplitude of the spontaneous mechanical activity showed stretch-dependency. Iberiotoxin, a selective blocker of BK(Ca) channels, potently increased contraction amplitude, and this effect was more prominent when muscle length was more than twice of its initial length. BK(Ca) channels seem activated more strongly to counteract enhanced spontaneous mechanical activity with UBSM stretch.
authors.affiliation: Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, 2-2-1 Miyama, Funabashi-City, Chiba 274-8510, Japan. yotanaka@phar.toho-u.ac.jp
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Takao
authors.initials: T
authors.lastname: Okamoto
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Imai
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Takahiro
authors.initials: T
authors.lastname: Horinouchi
authors.forename: Hikaru
authors.initials: H
authors.lastname: Tanaka
authors.forename: Katsuo
authors.initials: K
authors.lastname: Koike
authors.forename: Koki
authors.initials: K
authors.lastname: Shigenobu
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects*; D005260:Female; D006168:Guinea Pigs; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D010455:Peptides / Q000494:pharmacology*; D001743:Urinary Bladder / Q000187:drug effects
chemical_list: D002121:Calcium Channel Blockers; D015220:Calcium Channels; D010455:Peptides; C064719:iberiotoxin