Stimulation of phosphoinositide hydrolysis and inhibition of cyclic AMP formation by muscarinic agonists in developing chick heart.
Stimulation of phosphoinositide hydrolysis and inhibition of cyclic AMP formation by muscarinic agonists in developing chick heart.
复制标题
毒蕈碱激动剂在发育中的鸡心脏中刺激磷酸肌醇水解并抑制环 AMP 形成。
DOI：
10.1016/0006-2952(85)90512-x
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发表时间：
1985
影响因子：
5.8
通讯作者：
Brown,JH
中科院分区：
文献类型：
--
作者：
Orellana,SA;Brown,JH
在胚胎发育的第4天，胆碱能激动剂卡巴胆碱就能刺激胚胎心脏肌醇磷脂的水解。在4日龄雏鸡心脏中，卡巴胆碱对1-磷酸肌醇形成的半数刺激浓度为30μM，最大刺激浓度为1 mM。这些值与使用13天胚胎的心脏获得的值相同[J.H.Brown和S.L.Brown，J.Biol]。化学259、3777(1984)]。在氨基甲胆碱存在的情况下，每mg蛋白生成的[~3H]肌醇1-磷酸的量在幼龄时比在晚龄时多；因此，氨基甲胆碱的刺激作用从4天的8倍下降到13天的2倍。刺激M受体也能抑制异丙肾上腺素刺激的环状AMP的形成，最早在4d。异丙肾上腺素刺激的环磷酸腺苷在幼龄时升高最大，而卡巴胆碱的抑制作用保持在75%不变。在4天时，卡巴胆碱的半最大和最大抑制分别出现在0.3和30μM，与使用13天的心脏获得的值相同(见上文引用的参考文献)。因此，雏鸡胚胎心脏对M受体激动剂的两种生化反应具有相同的激动剂敏感性，且功能先于副交感神经支配和生理反应。
As early as 4 daysin ovo, phosphoinositide hydrolysis in embryonic chick heart was stimulated by the cholinergic agonist carbachol. In the 4-day chick heart, the concentrations of carbachol giving half-maximal and maximal stimulation of [3H]inositol 1-phosphate formation were 30 μM and 1 mM respectively. These values are identical to those obtained using hearts from 13-day embryos [J. H. Brown and S. L. Brown,J. biol. Chem.259, 3777 (1984)]. The amounts of [3H]inositol 1-phosphate formed per mg protein in the presence of carbachol were greater at early ages than at later ones; the stimulation by carbachol thus decreased from 8-fold at 4 days to 2-fold at 13 days. Muscarinic receptor stimulation also led to inhibition of isoproterenol-stimulated cyclic AMP formation as early as 4 days. The isoproterenol-stimulated increase in cyclic AMP was greatest at early ages, whereas the inhibitory effect of carbachol remained constant at 75%. At 4 days, half-maximal and maximal inhibition by carbachol occurred at 0.3 and 30 μM, respectively, the same values obtained using 13-day hearts (see reference cited above). Thus, the two biochemical responses of embryonic chick heart to muscarinic agonists have identical agonist sensitivities regardless of embryonic age and are functional prior to parasympathetic innervation and physiological responsiveness.