Cellular and molecular pharmacological studies on a role of tyrosine kinase in the signal transduction system in cardiac cells.

本文观察了酪氨酸激酶抑制剂对组胺通过H_1受体对豚鼠左心房的正性变力作用的影响，并用重组抗磷酸酪氨酸抗体评价了组胺引起的心肌蛋白酪氨酸残基磷酸化水平的变化。组胺的正性肌力作用被酪氨酸激酶抑制剂tyrphostin A25和染料木黄酮抑制，但不被非活性染料木黄酮类似物大豆苷元抑制。组胺在1 μ mol/L浓度下产生双组分正性肌力反应，包括初始增强相和第二和晚期发展的更大的正性肌力相。治疗与tyrphostin A25和染料木黄酮，但没有大豆黄酮，显着衰减的两个组件的变力性反应，虽然染料木黄酮抑制的初始组件比晚期组件更显着。组胺可诱导分子量约为30、35、85和120 kDa的四种主要蛋白质簇的酪氨酸磷酸化水平迅速而短暂地增加。组胺诱导的蛋白酪氨酸磷酸化可被H_1受体拮抗剂扑尔敏拮抗。我们的结论是，蛋白酪氨酸磷酸化的增加可能在启动豚鼠左心房H_1受体的正性变力效应中起重要作用。

The effects of tyrosine kinase inhibitors on the positive inotropic effect of histamine via H_1-receptors in guinea-pig left atria were examined and histamine-induced changes in phosphorylation levels of the cardiac proteins on tyrosine residues were evaluated using a recombinant antiphosphotyrosine antibody. The positive inotropic effect of histamine was depressed by the tyrosine kinase inhibitors tyrphostin A25 and genistein but not by the inactive genistein analogue daidzein. At a concentration of 1 umol/l histamine produced a dual-component positive inotropic response composed of an initial increasing phase and a second and late developing, greater positive inotropic phase. Treatment with tyrphostin A25 and genistein, but not daidzein, significantly attenuated the two components of the inotropic response, although genistein suppressed the initial component more markedly than the late component. Histamine induced a rapid but transient increase in tyrosine phosphorylation in four main clusters of proteins with approximately molecular weights of 30,35,85 and 120 kDa. histamine-induced protein tyrosine phosphorylation was antagonized by the H_1-receptor antagonist chlorpheniramine. We conclude that increased protein tyrosine phosphorylation may play an important role in initiating the positive inotropic effect of H_1-receptor stimulation in guinea-pig left atria.