二氢吡啶类药物Bay K 8644对大鼠离体输精管释放[3H]-去甲肾上腺素的影响。
Effect of the dihydropyridine Bay K 8644 on the release of [3H]-noradrenaline from the rat isolated vas deferens.
作者信息
Ceña V, García A G, Khoyi M A, Salaices M, Sanchez-García P
出版信息
Br J Pharmacol. 1985 Jul;85(3):691-6. doi: 10.1111/j.1476-5381.1985.tb10565.x.
The effects of Bay K 8644 on the release of [3H]-noradrenaline evoked by potassium, electrical stimulation or tyramine from the rat isolated vas deferens labelled with [3H]-noradrenaline were investigated. Bay K 8644 (1 microM) by itself did not affect the spontaneous release of tritium from the rat isolated vas deferens. However, it increased the calcium-dependent release of tritium elicited by both high potassium (59 mM) and electrical field stimulation. The exposure of rat vas deferens to phentolamine (10 microM) increased the release of tritium induced by potassium (59 mM) and electrical field stimulation. Bay K 8644 (1 microM) failed to increase further the release of tritium elicited by both stimuli in preparations previously treated with phentolamine (10 microM). The calcium-independent release of [3H]-noradrenaline evoked by tyramine (10 microM) was not affected by Bay K 8644 (1 microM). The results of our study support the view that alpha2-adrenoceptors modulate noradrenaline release by restricting calcium influx into sympathetic nerve terminals through voltage-dependent channels.
研究了Bay K 8644对用[3H]-去甲肾上腺素标记的大鼠离体输精管中由钾、电刺激或酪胺诱发的[3H]-去甲肾上腺素释放的影响。Bay K 8644（1微摩尔）本身并不影响大鼠离体输精管中氚的自发释放。然而，它增加了由高钾（59毫摩尔）和电场刺激引起的氚的钙依赖性释放。大鼠输精管暴露于酚妥拉明（10微摩尔）会增加由钾（59毫摩尔）和电场刺激诱导的氚的释放。在先前用酚妥拉明（10微摩尔）处理过的制剂中，Bay K 8644（1微摩尔）未能进一步增加由这两种刺激引起的氚的释放。酪胺（10微摩尔）诱发的[3H]-去甲肾上腺素的非钙依赖性释放不受Bay K 8644（1微摩尔）的影响。我们的研究结果支持这样一种观点，即α2-肾上腺素能受体通过限制钙通过电压依赖性通道流入交感神经末梢来调节去甲肾上腺素的释放。
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