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BioMed Research International
Volume 2018, Article ID 2925985, 9 pages
https://doi.org/10.1155/2018/2925985
Research Article

Regulation of Spontaneous Contractions in Intact Rat Bladder Strips and the Effects of Hydrogen Peroxide

1Department of Surgery, MetroHealth Medical Center, Case Western Reserve University, Cleveland, OH, USA
2Department of Urology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
3Division of Urogynecology, Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan
4Department of Urology, Shengjing Hospital, China Medical University, Shenyang, China

Correspondence should be addressed to Guiming Liu; ude.esac@uil.gnimiug

Received 23 August 2017; Revised 1 December 2017; Accepted 31 December 2017; Published 4 February 2018

Academic Editor: Kota V. Ramana

Copyright © 2018 Mingshuai Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Enhanced spontaneous contractions are associated with overactive bladder. Elevated levels of reactive oxygen species might contribute to enhanced spontaneous contractions. We investigated the regulation of spontaneous contractions and the effects of hydrogen peroxide (H2O2) in intact rat bladder strips. The spontaneous contractions were measured using a tissue bath system. The vehicle or the specific activators/blockers were applied and followed by the application of 0.003 g% H2O2. The basal tension, amplitude, and frequency of spontaneous contractions were quantified. Nisoldipine and bisindolylmaleimide 1 had no effects on spontaneous contractions. SKF96365 and Y27632 decreased basal tension and amplitude. Ryanodine slightly increased frequency. Both iberiotoxin and NS-1619 increased amplitude. Apamin reduced frequency but increased amplitude. NS-309 inhibited both the amplitude and frequency. The basal tension and amplitude increased when H2O2 was applied. Pretreatment with NS-309 inhibited H2O2-elicited augmented amplitude and frequency, while pretreatment with Y-27632 inhibited the augmented basal tension. The combined application of NS-309 and Y27632 almost eliminated spontaneous contractions and its augmentation induced by H2O2. In conclusion, Ca2+ influx, Rho kinase activation, and SK channel inactivation play important roles in spontaneous contractions in intact bladder strips, whereas only latter two mechanisms may be involved in H2O2-elicited increased spontaneous contractions.