【摘要】 目的:研究酪氨酸激酶是否参与α_1A肾上腺素受体介导的人胚胎肾细胞（HEK293）浆游离钙浓度调节。方法:用Fura-2/AM荧光法测定细胞游离钙浓度,底物反应法测定酪氨酸激酶活性。结果:去甲肾上腺素（NE）可引起的HEK293细胞内游离钙浓度升高至（371±31）nmol·L^-1,酪氨酸激酶抑制剂檞皮素和tyrphostin可抑制NE引起的细胞内游离钙浓度升高,但不抑制NE引起磷酸肌醇的生成,NE可引起HEK293细胞浆酪氨酸激酶升高1.73±0.72倍,这种作用可被PKC的抑制剂calphostin C和细胞内钙耗竭所抑制。结论:酪氨酸激酶参与α₁A肾上腺素受体介导的人胚胎肾细胞内游离钙浓度升高。更多还原

【Abstract】 AIM: To determine the role of protein-tyrosine kinase ( PTK ) in α1A-adrenoceptor-mediated increase of [ Ca2 + ] i ( intracellular calcium ) in human embryo kidney (HEK) 293 cells expressed α1A-adrenoceptor. METHODS: Effects of two PTK inhibitors; genistein and tyrphostin, were investigated on the increase of [Ca2+ ]i by using Fura-2, The activity of PTK was measured and the accumulation of [3H ] InsPs were observed. RESULTS: Norepinephrine stimulated a rapid increase in [Ca2+ ]i to (371 ± 31) nmol·L-1 in HEK 293 cells. Norepinephrine-induced increase of [Ca2+ ]i was inhibited by the tyrosine kinase inhibitors quercetin and tyrphostin by 23.8 % and 21.4 %, respectively, but the accumulation of [3H]InsPs induced by norepinephrine was not. The activity of the plasma-associated tyrosine kinase was increased to (1.73±0.72)-fold over the control by norepinephrine 10 μmol·L-1. The norepinephrine-activated PTK was inhibited by calphostin C and depletion of intra- and extra-cellular Ca2+ . CONCLUSION: The PTK participates in mobilization of Ca2+ mediated by α1A-adrenoceptors in HEK 293 cell lines.更多还原