Brouwer R M, Wenting G J, Schalekamp M A
Department of Internal Medicine I, University Hospital Rotterdam Dijkzigt, The Netherlands.
J Cardiovasc Pharmacol. 1990 Jun;15(6):868-76. doi: 10.1097/00005344-199006000-00003.
This study evaluates the vasoactive effects and mode of action of ketanserin, a selective 5HT2 receptor antagonist, on digital circulation in 11 patients with primary Raynaud's phenomenon. Reflex digital vasoconstriction was induced by moderate body cooling. We found that ketanserin given intravenously in a dose of 10 mg, normalized digital skin temperature and digital blood flow as estimated by venous occlusion plethysmography and laser-Doppler flowmetry. However, effects of ketanserin on transcutaneously measured oxygen pressure were modest. This could imply a preferential effect of ketanserin on arteriovenous shunt flow. Pretreatment with high doses of the selective and nonselective alpha-adrenoreceptor antagonists prazosin and phentolamine did not abolish the effects of ketanserin on digital blood flow. However, under alpha-adrenoceptor blockade the small effects of ketanserin on normal blood pressure disappeared. Thus, in contrast to the effects in the systemic circulation, the principal mechanism underlying digital vasodilation after ketanserin is unlikely to involve alpha-adrenoceptor antagonism. We conclude that 5HT2 receptors are present in the digital vasculature. In patients with primary Raynaud's phenomenon, their activation plays an important role in cold-induced digital vasoconstriction.
本研究评估了选择性5-羟色胺2（5HT2）受体拮抗剂酮色林对11例原发性雷诺现象患者手指循环的血管活性作用及作用方式。通过适度降低体温诱发手指反射性血管收缩。我们发现，静脉注射10毫克酮色林可使手指皮肤温度以及通过静脉阻断体积描记法和激光多普勒血流仪估算的手指血流量恢复正常。然而，酮色林对经皮测量的氧分压影响不大。这可能意味着酮色林对动静脉分流血流具有优先作用。用高剂量的选择性和非选择性α-肾上腺素能受体拮抗剂哌唑嗪和酚妥拉明预处理并不能消除酮色林对手指血流量的影响。然而，在α-肾上腺素能受体阻断情况下，酮色林对正常血压的微小影响消失了。因此，与在体循环中的作用不同，酮色林后手指血管舒张的主要机制不太可能涉及α-肾上腺素能受体拮抗作用。我们得出结论，手指血管系统中存在5HT2受体。在原发性雷诺现象患者中，其激活在寒冷诱发的手指血管收缩中起重要作用。
