INNES I R
Br J Pharmacol Chemother. 1962 Dec;19(3):427-41. doi: 10.1111/j.1476-5381.1962.tb01447.x.
Contractions of isolated strips of cat spleen due to 5-hydroxytryptamine, adrenaline, histamine and acetylcholine were antagonized by phenoxybenzamine. Responses to both 5-hydroxytryptamine and adrenaline were not blocked in strips which were protected by a high concentration of either 5-hydroxytryptamine or adrenaline throughout exposure to phenoxybenzamine. The contraction due to a large dose of 5-hydroxytryptamine lasted less than 1 hr even when the drug was still present. Strips thus desensitized to 5-hydroxytryptamine responded normally to acetylcholine and histamine but did not respond to adrenaline. The actions of 5-hydroxytryptamine and adrenaline were blocked by 2-bromolysergic acid diethylamide or by dihydroergotamine. These results indicated that 5-hydroxytryptamine and adrenaline act on the same receptors. Cocaine potentiated the action of adrenaline but inhibited the action of 5-hydroxytryptamine. The sensitivity to 5-hydroxytryptamine of spleen strips from cats treated 24 hr earlier with reserpine was only one-fiftieth of that of normal strips. Cocaine potentiated the action of 5-hydroxytryptamine on strips from reserpine-treated cats. A high concentration of 5-hydroxytryptamine in spleen strips from reserpine-treated cats and in cocaine-treated strips prevented phenoxybenzamine from blocking the actions of adrenaline. The effects of tyramine on spleen strips almost exactly paralleled the effects of 5-hydroxytryptamine. Strips showing tachyphylaxis to tyramine did not respond to 5-hydroxytryptamine. It is concluded that 5-hydroxytryptamine has a dual action, viz., a major action due to release of stored noradrenaline and a minor direct action of adrenaline receptors.
苯氧苄胺可拮抗5-羟色胺、肾上腺素、组胺和乙酰胆碱引起的猫脾脏离体条带收缩。在整个苯氧苄胺作用期间，用高浓度的5-羟色胺或肾上腺素保护的条带中，对5-羟色胺和肾上腺素的反应均未被阻断。即使药物仍存在，大剂量5-羟色胺引起的收缩持续时间也不到1小时。对5-羟色胺脱敏的条带对乙酰胆碱和组胺反应正常，但对肾上腺素无反应。5-羟色胺和肾上腺素的作用可被2-溴麦角酰二乙胺或二氢麦角胺阻断。这些结果表明5-羟色胺和肾上腺素作用于相同的受体。可卡因增强肾上腺素的作用，但抑制5-羟色胺的作用。24小时前用利血平处理过的猫的脾脏条带对5-羟色胺的敏感性仅为正常条带的五十分之一。可卡因增强5-羟色胺对利血平处理过的猫的条带的作用。利血平处理过的猫的脾脏条带和可卡因处理过的条带中高浓度的5-羟色胺可阻止苯氧苄胺阻断肾上腺素的作用。酪胺对脾脏条带的作用几乎与5-羟色胺的作用完全平行。对酪胺出现快速耐受性的条带对5-羟色胺无反应。结论是5-羟色胺具有双重作用，即主要作用是由于储存的去甲肾上腺素释放，次要作用是直接作用于肾上腺素受体。
