Mena M A, Vidrio H
J Cardiovasc Pharmacol. 1979 Jan-Feb;1(1):149-54. doi: 10.1097/00005344-197901000-00014.
In view of the conflicting reports of both constrictor and dilator effects of serotonin on the external carotid vascular bed of dogs, the influence of intraarterial infusions of the amine on blood flow through this territory was assessed by electromagnetic flowmeter techniques. In anesthetized intact dogs, serotonin produced dose-related increases in flow. These vasodilator responses were markedly diminished after ipsilateral vagotomy and were followed by delayed vasoconstriction, which then became the predominant response. Pretreatment with atropine did not modify dilator responses, while resection of the ipsilateral stellate ganglion reversed them to pure constriction. In the internal carotid, serotonin elicited constriction, and this effect was unaffected by vagotomy. These results were interpreted in terms of the hypothesis relating serotonin reactivity to vascular tone. The amine would elicit dilatation through an effect on tonically constricted small vessels. Removal of this tone by section of the vagosympathetic trunk or stellectomy would unmask the constrictor effect of serotonin on large vessels. Such reversal of responses would not occur in the internal carotid, a territory normally devoid of important sympathetic tone.
鉴于关于血清素对犬颈外血管床的收缩和舒张作用存在相互矛盾的报道，采用电磁流量计技术评估了动脉内输注该胺对通过该区域的血流的影响。在麻醉的完整犬中，血清素使血流量呈剂量相关增加。同侧迷走神经切断术后，这些血管舒张反应明显减弱，随后出现延迟性血管收缩，后者继而成为主要反应。阿托品预处理并未改变舒张反应，而切除同侧星状神经节则使其转变为单纯的收缩反应。在颈内动脉，血清素引起收缩，且该效应不受迷走神经切断术的影响。这些结果是根据将血清素反应性与血管张力相关联的假说来解释的。该胺通过对张力性收缩的小血管产生作用而引起扩张。切断迷走交感干或进行星状神经节切除术消除这种张力，将揭示血清素对大血管的收缩作用。在颈内动脉，这种反应逆转不会发生，因为该区域通常没有重要的交感神经张力。
