Marín J, Salaices M, Marco E J, Gómez B, Lluch S
J Pharm Pharmacol. 1979 Jul;31(7):456-9. doi: 10.1111/j.2042-7158.1979.tb13553.x.
5-Hydroxytryptamine (5-HT) induced dose-dependent increases in tension on the isolated posterior communicating artery (PCA) of the cat were significantly antagonized by lysergic acid diethylamide (LSD, 6 X 10(-9). In the presence of the phentolamine (10(-6) M) the contraction induced by the two lowest doses of 5-HT was significantly reduced. Pretreatment of the animals with reserpine (3 mg kg-1, i.p., total dose) did not modify the dose-response curve to 5-HT except for the lowest dose. Removal of both superior cervical sympathetic ganglia 15 days before the experiment brought about a significant increase in the vasoconstriction induced by 5-HT at all the doses compared with the control. Cocaine (10(-6) M) induced a significant shift to the left of the dose-response curve to 5-HT but the maximum response was the same as in the control. The augmented response to 5-HT after denervation was partially antagonized by LSD (6 X 10(-9) M) but not by phentolamine (10(-6) M). These results show that the vasoconstriction elicited by 5-HT in the PCA of the cat is mainly due to direct stimulation of tryptaminergic receptors. The participation of an indirect adrenergic component in the contractile effects of 5-HT seems to be negligible.
5-羟色胺（5-HT）可使猫离体后交通动脉（PCA）的张力呈剂量依赖性增加，而麦角酸二乙胺（LSD，6×10⁻⁹）可显著拮抗这种作用。在酚妥拉明（10⁻⁶ M）存在的情况下，5-HT最低的两个剂量所诱导的收缩作用显著减弱。用利血平（3 mg·kg⁻¹，腹腔注射，总剂量）对动物进行预处理，除最低剂量外，并未改变对5-HT的剂量反应曲线。在实验前15天切除双侧颈上神经节，与对照组相比，所有剂量的5-HT所诱导的血管收缩作用均显著增强。可卡因（10⁻⁶ M）可使5-HT的剂量反应曲线显著左移，但最大反应与对照组相同。去神经后对5-HT增强的反应部分被LSD（6×10⁻⁹ M）拮抗，但未被酚妥拉明（10⁻⁶ M）拮抗。这些结果表明，5-HT在猫PCA中所引发的血管收缩主要是由于对色胺能受体的直接刺激。5-HT收缩作用中间接肾上腺素能成分的参与似乎可以忽略不计。
