Khoyi M A, Pousti A, Zarrindast M R
Br J Pharmacol. 1974 Dec;52(4):579-84. doi: 10.1111/j.1476-5381.1974.tb09726.x.
1 The effect of ethacrynic acid (EA) was studied on guinea-pig and rat vas deferens in vitro.2 EA contracted the guinea-pig but not the rat vas deferens in a dose-dependent manner (50-800 mug/ml). Tyramine caused contraction in 10 out of 18 guinea-pig vas deferens; EA caused contraction in 17 of the preparations which did not respond to tyramine. Repeated doses of EA produced tachyphylaxis, but there was no cross tachyphylaxis to tyramine.3 The contractions produced by EA were prevented by phentolamine or reserpine pretreatment and potentiated by cocaine. A low concentration of desipramine (3 ng/ml) potentiated and higher concentrations (0.6 and 3.0 mug/ml) inhibited the response of vas deferens to EA.4 Hexamethonium (100 mug/ml) or atropine (0.1 mug/ml) did not inhibit the effect of EA, excluding the nicotinic and muscarinic receptors as the sites of action.5 The effect of noradrenaline (NA) on the guinea-pig and rat vas deferens was enhanced by EA pretreatment, which may be due to inhibition of NA uptake.6 It is concluded that EA releases NA from guinea-pig vas deferens. The mechanism of release seems to be different from that of tyramine.
研究了依他尼酸（EA）对豚鼠和大鼠离体输精管的作用。
EA能使豚鼠输精管呈剂量依赖性收缩（50 - 800微克/毫升），但对大鼠输精管无此作用。18条豚鼠输精管中有10条对酪胺产生收缩反应；在对酪胺无反应的17条标本中，EA能使其产生收缩。重复给予EA可产生快速耐受性，但对酪胺无交叉快速耐受性。
酚妥拉明或利血平预处理可抑制EA引起的收缩，而可卡因可增强该收缩。低浓度的地昔帕明（3纳克/毫升）可增强收缩，而较高浓度（0.6和3.0微克/毫升）则抑制输精管对EA的反应。
六甲铵（100微克/毫升）或阿托品（0.1微克/毫升）不抑制EA的作用，排除了烟碱样和毒蕈碱样受体作为作用位点。
预先给予EA可增强去甲肾上腺素（NA）对豚鼠和大鼠输精管的作用，这可能是由于抑制了NA的摄取。
得出结论：EA可使豚鼠输精管释放NA。其释放机制似乎与酪胺不同。
