5-Hydroxytryptamino-induced calcium sparks in cultured rat stomach fundus smooth muscle cells  

作　　者：张小玲 阎宏涛 闫炀 

机构地区：[1]Department of Chemistry, Northwest University, Xian 710069, China [2]Medical College, Xi'an Jiaotong University, Xian 710061, China

出　　处：《Science China Chemistry》2003年第1期13-18,共6页中国科学（化学英文版）

摘　　要：With a new fluorescence probe of Ca2+, STDIn-AM, 5-hydroxytryptamino (5-HT)-induced spontaneous calcium release events (calcium sparks) in cultured rat stomach fundus smooth mus-cle cells (SFSMC) are investigated by laser scanning confocal microscope. The mechanisms of initiation of Ca2+ sparks, propagating Ca2+ waves and their relation to E-C coupling are discussed. After the extracellular [Ca2+] is increased to 10 mmol/L, addition of 5-HT causes hot spots throughout the cytoplasm, which is brighter near the plasmalemma. The amplitude of the event is at least two times greater than the standard deviation of fluorescence intensity fluctuations meas-ured in the neighboring region and the duration of the Ca2+ signal is over 100 ms. The results sug-gest that 5-HT acts by the way of 5-HT2 receptors on SFSMC, then through 5-HT2 receptors cou-ples IP3/Ca2+ and DG/PKC double signal transduction pathways to cause Ca2+ release from intra-cellular Ca2+ stores and followed Ca2+ influx possibly through calcium release-activated calcium influx. The acceptor of activated 5-HT2 can also cause membrane depolarization, which then stimulates the L-type Ca2+ channels leading to Ca2+ influx. Then the local Ca2+ entry mentioned above activates ryanodine-sensitive Ca2+ release channels (RyR) on sarcoplasmic reticulum (SR) to cause local Ca2+ release events (Ca2+ sparks) through calcium-induced calcium release (CICR).With a new fluorescence probe of Ca2+, STDIn-AM, 5-hydroxytryptamino (5-HT)-induced spontaneous calcium release events (calcium sparks) in cultured rat stomach fundus smooth muscle cells (SFSMC) are investigated by laser scanning confocal microscope. The mechanisms of initiation of Ca2+ sparks, propagating Ca2+ waves and their relation to E-C coupling are discussed. After the extracellular [Ca2+] is increased to 10 mmol/L, addition of 5-HT causes hot spots throughout the cytoplasm, which is brighter near the plasmalemma. The amplitude of the event is at least two times greater than the standard deviation of fluorescence intensity fluctuations measured in the neighboring region and the duration of the Ca2+ signal is over 100 ms. The results suggest that 5-HT acts by the way of 5-HT2 receptors on SFSMC, then through 5-HT2 receptors couples IP3/Ca2+ and DG/PKC double signal transduction pathways to cause Ca2+ release from intracellular Ca2+ stores and followed Ca2+ influx possibly through calcium release-activated calcium influx. The acceptor of activated 5-HT2 can also cause membrane depolarization, which then stimulates the L-type Ca2+ channels leading to Ca2+ influx. Then the local Ca2+ entry mentioned above activates ryanodine-sensitive Ca2+ release channels (RyR) on sarcoplasmic reticulum (SR) to cause local Ca2+ release events (Ca2+ sparks) through calcium-induced calcium release (CICR).

关 键 词：calcium spark  new fluorescence probe of Ca2+  STOMACH FUNDUS smooth muscle cells  5-hydroxytryptamino  laser scanning CONFOCAL microscope. 

分 类 号：R333[医药卫生—人体生理学]