Arner M, Högestätt E D
Acta Physiol Scand. 1986 Oct;128(2):209-17. doi: 10.1111/j.1748-1716.1986.tb07968.x.
The postjunctional receptors mediating contractile responses to noradrenaline (NA) and 5-hydroxytryptamine (5-HT) were characterized in ring segments of human hand veins by using subtype selective agonists and antagonists. The mechanical characteristics of the preparations were also examined by length-tension measurements. The length-active wall tension curve was bell-shaped and reached a maximum at a length corresponding to a passive distending pressure of approximately 14 mmHg. (-)-Phenylephrine consistently contracted the veins and was 24 times less potent than (+/-)-NA whereas clonidine produced a contraction in only two out of 11 vessel segments. Neither prazosin nor rauwolscine competitively inhibited the contractile response to NA, and large inter-individual differences were found in the degree of inhibition produced by the antagonists. However, application of both prazosin and rauwolscine almost abolished the NA-induced contraction. Ketanserin and methergoline inhibited the contractile response to 5-HT; the former in an apparently competitive manner with a pA2 value of 8.94, whereas the latter substantially reduced the maximum 5-HT response. It is suggested that NA elicits contraction in human hand veins by acting at a mixed population of alpha 1- and alpha 2-adrenoreceptors. The contractile response to 5-HT, on the other hand, appears to be mediated predominantly by 5-HT2 receptors.
利用亚型选择性激动剂和拮抗剂，对人手部静脉环段中介导去甲肾上腺素（NA）和5-羟色胺（5-HT）收缩反应的接头后受体进行了表征。还通过长度-张力测量研究了标本的力学特性。长度-活性壁张力曲线呈钟形，在对应于约14 mmHg被动扩张压力的长度处达到最大值。（-）-去氧肾上腺素始终使静脉收缩，其效力比（±）-NA低24倍，而可乐定仅在11个血管段中的2个中引起收缩。哌唑嗪和萝芙木碱均未竞争性抑制对NA的收缩反应，并且拮抗剂产生的抑制程度存在较大的个体差异。然而，同时应用哌唑嗪和萝芙木碱几乎消除了NA诱导的收缩。酮色林和麦角新碱抑制对5-HT的收缩反应；前者以明显竞争性的方式，pA2值为8.94，而后者则大幅降低了最大5-HT反应。提示NA通过作用于α1-和α2-肾上腺素能受体的混合群体来引起人手部静脉收缩。另一方面，对5-HT的收缩反应似乎主要由5-HT2受体介导。
