Actin microfilament involved in regulation of pacemaking activity increased by membrane stretch in cultured ICCs from murine intestine
会议名称：《中国生理学会第23届全国会员代表大会暨生理学学术大会》
会议日期：2010年
学科分类：1001[医学-基础医学(可授医学、理学学位)] 10[医学]
基 金：supported by the National Natural Science Foundation of China(No.10672103)
关 键 词：ICCs membrane stretch actin microfilament pacemaking activity calcium oscillation.
摘 要：Distension is a regular mechanical stimulus in gastrointestinal(GI) *** study is designed to investigate the effect of membrane stretch on pacemaking activity and whether actin microfilament is involved in its mechanism in cultured murine intestinal interstitial cells of Cajal(ICCs) by using whole-cell patch-clamp and calcium imaging *** stretch induced sustained inward holding current from the baseline to(647.38±105.07) pA and significantly decreased amplitudes of pacemaker current from(222.25±51.76) pA to(141.17±46.45) pA(n=6,P0.05).Membrane stretch increased the intensity of basal F/F0 from baseline to(1.09±0.03) and significantly increased of Ca oscillation amplitude from(0.08±0.01) to(0.19±0.03)(ΔF/F0)(n=6,P0.05).20μmol/L cytochalasin-B,a disruptor of actin microfilaments,significantly suppressed amplitude of pacemaker currents and calcium oscillations from(491.32±160.33) pA and(0.30±0.06)(ΔF/F0) to(233.12±92.00) pA and(0.09±0.02) (ΔF/F0)(n=6,P0.05),***-B blocked membrane stretch-induced increase of pacemaker currents and calcium oscillations.20μmol/L phalloidin,a stabilizer of actin microfilaments,significantly enhanced amplitude of pacemaker currents and calcium oscillations from(751.79±282.82) pA and(0.56±0.13)(ΔF/F0) to (1234.34±607.83) pA and(0.72±0.08)(ΔF/F0)(n=6,P0.05),*** stretch still induced an inward holding current and increased basal fluorescence intensity from baseline to(1.32±0.07) when pretreatment with *** results suggest that membrane stretch potentiates pacemaking activity via actin microfilaments and the process is mediated by altering intracellular basal calcium concentration and calcium oscillation in cultured intestinal ICCs.