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Updated: Aug 19, 2026

Bladder Smooth Muscle Strip Contractility as a Method to Evaluate Lower Urinary Tract Pharmacology
Published on: August 18, 2014
Bk(Ca) channel activity enhances with muscle stretch in guinea-pig urinary bladder smooth muscle
Yoshio Tanaka1, Takao Okamoto, Toshiyasu Imai
1Department 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
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.
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