Verdouw P D, Jennewein H M, Heiligers J, Duncker D J, Saxena P R
Eur J Pharmacol. 1984 Jul 20;102(3-4):499-509. doi: 10.1016/0014-2999(84)90571-5.
The study concerned effects of ketanserin and a new 5-HT2 receptor antagonist, Wal 1307, on the responses to 5-hydroxytryptamine (5-HT) in the porcine common carotid vascular bed. More than 80% of the total carotid blood flow (208 +/- 18 ml; n = 12) bypassed the tissues via arteriovenous anastomoses. Intracarotid infusions of 5-HT (2 micrograms X kg-1 X min-1) reduced the total carotid blood flow by about 50% and arteriovenous anastomotic flow by 85% but extracerebral tissue (nutrient) blood flow more than tripled. The cerebral component did not change. Thus, 5-HT appears to constrict large conducting arteries and arteriovenous anastomoses but dilates arterioles. Ketanserin and Wal 1307 did not affect carotid blood flow distribution but completely blocked the amine-induced reduction of total carotid blood flow. The constriction of arteriovenous anastomoses was only slightly reduced but the 5-HT-induced arteriolar, vasodilation was enhanced. We conclude that vasoconstriction in the main trunk of the carotid artery and, to a smaller degree, in the arteriovenous anastomoses and arterioles, is mediated by mediated by 5-HT2 receptors. The major part of the constriction of arteriovenous anastomoses and arteriolar dilation elicited by 5-HT is, however, not mediated by 5-HT2 receptors. It is argued that these 'atypical' 5-HT receptors may be related to 5-HT1 binding sites.
该研究关注了酮色林和一种新型5-羟色胺2（5-HT2）受体拮抗剂Wal 1307对猪颈总动脉血管床中5-羟色胺（5-HT）反应的影响。超过80%的颈总动脉总血流量（208±18毫升；n = 12）通过动静脉吻合支绕过组织。颈内注射5-HT（2微克·千克⁻¹·分钟⁻¹）使颈总动脉总血流量减少约50%，动静脉吻合支血流量减少85%，但脑外组织（营养）血流量增加了两倍多。脑部血流量成分未改变。因此，5-HT似乎使大的传导动脉和动静脉吻合支收缩，但使小动脉扩张。酮色林和Wal 1307不影响颈动脉血流分布，但完全阻断了胺诱导的颈总动脉总血流量减少。动静脉吻合支的收缩仅略有减少，但5-HT诱导的小动脉血管舒张增强。我们得出结论，颈动脉主干以及程度较小的动静脉吻合支和小动脉中的血管收缩是由5-HT2受体介导的。然而，5-HT引起的动静脉吻合支收缩和小动脉扩张的主要部分并非由5-HT2受体介导。有人认为这些“非典型”5-HT受体可能与5-HT1结合位点有关。
