Araki K, Gomi Y
J Pharmacobiodyn. 1982 Oct;5(10):796-802. doi: 10.1248/bpb1978.5.796.
Effects of cocaine on the isotonic contractions of isolated vas deferens of intact and reserpinized guinea pigs to acetylcholine were examined. Both cocaine-induced increase in sensitivity to acetylcholine and cocaine-induced increase in maximum response of Ca2+-contraction was attenuated remarkably by reserpine. However, cocaine-induced increases in acetylcholine- and K+-contractions in Ca2+-free Tyrode solution were not prevented by reserpine. Acetylcholine-contraction, but not K+-contraction, in the preparation exposed for 5 min to Ca2+-free Tyrode solution were inhibited by reserpine. Cocaine did not inhibit the cholinesterase activity of vas deferens of guinea pig. These results suggested that presynaptic mechanisms of cocaine-induced supersensitivity are excluded and that inhibitory effect of reserpine on cocaine-induced supersensitivity might be due to the inhibition of cocaine-induced increase in calcium-influx into smooth muscle cells of vas deferens.
研究了可卡因对完整和利血平化豚鼠离体输精管对乙酰胆碱等张收缩的影响。利血平可显著减弱可卡因诱导的对乙酰胆碱敏感性增加以及可卡因诱导的Ca2+收缩最大反应增加。然而，在无Ca2+的台氏液中，利血平并不能阻止可卡因诱导的乙酰胆碱和K+收缩增加。暴露于无Ca2+台氏液5分钟的标本中，利血平可抑制乙酰胆碱收缩，但不抑制K+收缩。可卡因不抑制豚鼠输精管的胆碱酯酶活性。这些结果表明，可卡因诱导超敏反应的突触前机制被排除，利血平对可卡因诱导超敏反应的抑制作用可能是由于抑制了可卡因诱导的输精管平滑肌细胞钙内流增加。
