Benfey B G, Cohen J, Kunos G, Vermes-Kunos I
Br J Pharmacol. 1974 Apr;50(4):581-5. doi: 10.1111/j.1476-5381.1974.tb08592.x.
1 5-Hydroxytryptamine increased the contractility of the isolated rat atrium and produced a small rise in cyclic 3',5'-adenosine monophosphate (cyclic AMP) accumulation in rat heart slices. These effects were similar to those of tyramine.2 Incubation with phenoxybenzamine prevented the inotropic effect of 5-hydroxytryptamine but did not inhibit the rise in cyclic AMP accumulation.3 A single injection of reserpine 24 h before the experiment did not inhibit the inotropic effect of 5-hydroxytryptamine but prevented the rise in cyclic AMP accumulation.4 It is concluded that in the rat 5-hydroxytryptamine increases cardiac contractility chiefly by a direct effect which is blocked by phenoxybenzamine, whereas it increases myocardial cyclic AMP accumulation indirectly by releasing endogenous catecholamines. Cardiac contractility may thus be increased without a rise in cyclic AMP accumulation, and cyclic AMP accumulation may be increased without a rise in contractility.
5-羟色胺可增强离体大鼠心房的收缩力，并使大鼠心脏切片中的环磷腺苷（cAMP）积累略有增加。这些作用与酪胺的作用相似。
用酚苄明孵育可阻止5-羟色胺的变力作用，但不抑制cAMP积累的增加。
实验前24小时单次注射利血平不抑制5-羟色胺的变力作用，但可阻止cAMP积累的增加。
得出结论：在大鼠中，5-羟色胺主要通过一种被酚苄明阻断的直接作用来增强心脏收缩力，而它通过释放内源性儿茶酚胺间接增加心肌cAMP积累。因此，心脏收缩力可能在cAMP积累不增加的情况下增强，而cAMP积累可能在收缩力不增加的情况下增加。
