Asano M, Hidaka H
Br J Pharmacol. 1980 Aug;69(4):639-46. doi: 10.1111/j.1476-5381.1980.tb07915.x.
1 The potentiating effect of a low concentration of various vascular contractile agonists on the response of rabbit aortic strips to acetylcholine was examined. 2 A marked parallel displacement to the left (potentiation; not additive effect) of the dose-response curve for acetylcholine was observed when 5-hydroxytryptamine (5-HT), noradrenaline, histamine, angiotensin II or KCl were added at a concentration that caused only slight contraction (0.2 to 0.3 g) in the strips. This leftward displacement (potentiation) of the dose-response curve by these agonists was reversed to the control response curve by the respective blocking agents for each agonist, although the blocking agents themselves did not shift the acetylcholine dose-response curve to the right. Atropine produced a rightward displacement of the dose-response curve for acetylcholine. 3 The addition of an extremely low concentration of 5-HT or KCl which did not cause contraction, also produced a potentiation. 4 The order of potency of the agonists in potentiating the acetylcholine-induced contraction was KCl > 5-HT greater than or equal to histamine greater than or equal to angiotensin II > noradrenaline. 5 The contractile response of aortic strips to carbamylcholine was also potentiated by these agonists. 6 The results suggest that the potentiation by these agonists was not mediated through muscarinic receptors but through the respective receptors for each agonist.
研究了低浓度的各种血管收缩激动剂对兔主动脉条对乙酰胆碱反应的增强作用。
当以仅引起条带轻微收缩（0.2至0.3克）的浓度添加5-羟色胺（5-HT）、去甲肾上腺素、组胺、血管紧张素II或氯化钾时，观察到乙酰胆碱剂量反应曲线明显向左平行移位（增强；而非相加作用）。这些激动剂引起的剂量反应曲线向左移位（增强）可被每种激动剂的相应阻断剂逆转至对照反应曲线，尽管阻断剂本身并未使乙酰胆碱剂量反应曲线向右移位。阿托品使乙酰胆碱剂量反应曲线向右移位。
添加极低浓度的不引起收缩的5-HT或氯化钾也产生了增强作用。
激动剂在增强乙酰胆碱诱导的收缩方面的效力顺序为氯化钾>5-HT≥组胺≥血管紧张素II>去甲肾上腺素。
这些激动剂也增强了主动脉条对氨甲酰胆碱的收缩反应。
结果表明，这些激动剂的增强作用不是通过毒蕈碱受体介导的，而是通过每种激动剂各自的受体介导的。
