敲除Annexin A7基因的小鼠早期胚胎心肌细胞钙稳态正常

目的:研究Annexin A7在早期胚胎发育过程中对钙平衡调节的作用. 方法: 利用钙成像技术和膜片钳技术检测敲除Annexin A7小鼠的早期胚胎心肌细胞的钙平衡以及相应的离子通道的特性. 结果: 在胚胎心肌细胞发育的早期,敲除Annexin A7小鼠胚胎心肌细胞的静息钙(340/380荧光比例 0.78±0.02)、钙峰值(340/380荧光比例1.28±0.05)和正常细胞的值相似;动作电位(APD90 242.7±43.7 ms、最大去极化电位56.8±1.7 mV)以及L-型钙电流密度(14.1±2.5 pA/pF)和正常细胞的相似,并且钙电流能被碳酰胆碱减小(51.7±8)%,也和正常细胞相似. 结论: 敲除Annexin A7基因的小鼠早期胚胎心肌细胞具有正常的钙稳态以及正常的离子通道.

Early embryonic cardiomyocytes of Anxa7-/- mice display normal Ca2+ homeostasis

AIM: To study the involvement of Annexin A7 in the regulation of Ca2+ homeostasis in embryonic development stage. METHODS: Single cell Ca2+ imaging techniques and patch clamp technique were used to test the current of ion channel and action potential of Annexin A7 knock out mice embryonic heart cells. RESULTS: During early embryonic development (E11.5/E12.5) resting Ca2+ (ratio 0.78±0.02), values of peak Ca2+ concentration (ratio 1.28±0.05, n=30) were quite same to control cells. Anxa7-/- cardiomyocytes displayed normal action potentials (APD90 242.7±43.7 ms, a maximum diastolic potential of 56.8±1.7 mV) , and the density of L-type Ca2+-currents in Anxa7-/- cardiomyocytes (14.1±2.5 pA/pF) were quite same to control cells. Especially basal ICa was depressed by CCh (1 μmol*L-1) by (51.7±8)%. CONCLUSION: Early embryonic cardiomyocytes of Anxa7-/- mice display intact Ca2+ homeostasis and express all the components required for excitation contraction coupling.