Lee W H, Fujiwara M
Arzneimittelforschung. 1977;27(6):1149-53.
Effects of catecholamines on the contraction of isolated guinea-pig gallbladder induced by transmural stimulation (TM) were investigated. Tetrodotoxin and atropine prevented the TM-induced contraction. Atropine, but not tetrodotoxin, blocked the acetylcholine-induced contraction. Furthermore, the TM-induced contraction was sharply reduced during a cold storage for 1 to 4 days and then abolished 4 to 7 days later. Norepinephrine (5 X 10(-6) M) and epinephrine (4.5 X 10(-6) M) did not affect acetylcholine-induced contraction, but reduced the contractile response to TM by about 40% and 60%, respectively. Phentolamine, but not propranolol, abolished the inhibitory effects of norepinephrine and epinephrine on the contraction induced by TM. Isoproterenol and phenylephrine did not significantly modify the TM-induced contraction. These observations suggest that TM-induced contraction is produced by the release of acetylcholine from the ending of postganglionic cholinergic fibers. The possibility that norepinephrine and epinephrine act on the inhibitory alpha-adrenoreceptors in the ending of cholinergic neuron is discussed.
研究了儿茶酚胺对经壁刺激（TM）诱导的豚鼠离体胆囊收缩的影响。河豚毒素和阿托品可阻止TM诱导的收缩。阿托品可阻断乙酰胆碱诱导的收缩，但河豚毒素不能。此外，在冷藏1至4天期间，TM诱导的收缩急剧减少，然后在4至7天后消失。去甲肾上腺素（5×10⁻⁶ M）和肾上腺素（4.5×10⁻⁶ M）不影响乙酰胆碱诱导的收缩，但分别使对TM的收缩反应降低约40%和60%。酚妥拉明可消除去甲肾上腺素和肾上腺素对TM诱导收缩的抑制作用，而普萘洛尔则不能。异丙肾上腺素和去氧肾上腺素对TM诱导的收缩无明显影响。这些观察结果表明，TM诱导的收缩是由节后胆碱能纤维末梢释放乙酰胆碱所致。文中讨论了去甲肾上腺素和肾上腺素作用于胆碱能神经元末梢抑制性α-肾上腺素能受体的可能性。
