van Zwieten P A, Mathy M J, Boddeke H W, Doods H N
Division of Pharmacotherapy, Faculty of Medicine, University of Amsterdam, The Netherlands.
J Cardiovasc Pharmacol. 1987;10 Suppl 3:S54-8.
Ketanserin, when infused into the left thoracic vertebral artery of chloralose-anaesthetized cats, induced a significantly stronger hypotensive effect than when administered via the systemic circulation. The effect of ketanserin, which is initiated most likely in the pontomedullary region of the brain, proved to be dose dependent. The central hypotensive effect of ketanserin was accompanied by modest bradycardia, which was probably also of central nervous origin. The selective 5-HT2-receptor antagonist ritanserin, when infused into the left vertebral artery, did not lower blood pressure or heart rate, thus suggesting that central 5-HT2 receptors do not play a significant role in the initiation of ketanserin's central hypotensive action. Similarly, neither alpha 1- nor alpha 2-adrenoceptors in the central nervous system (CNS) appear to be involved in the hypotensive action of ketanserin, as concluded from pretreatment experiments with corynanthine and rauwolscine, respectively. The central hypotensive action could be blocked by atropine. This effect is located within the CNS but does not implicate a direct influence of ketanserin on CNS muscarinic receptors.
在给氯醛糖麻醉的猫的左胸段椎动脉注入酮色林时，其降压作用比经体循环给药时显著更强。酮色林的作用最有可能始于脑桥延髓区域，且呈剂量依赖性。酮色林的中枢性降压作用伴有轻度心动过缓，这可能也源于中枢神经系统。选择性5-羟色胺2（5-HT2）受体拮抗剂利坦色林注入左椎动脉时，不会降低血压或心率，因此表明中枢5-HT2受体在酮色林的中枢性降压作用起始过程中不起重要作用。同样，分别用育亨宾和萝芙辛预处理实验得出，中枢神经系统（CNS）中的α1和α2肾上腺素受体似乎均未参与酮色林的降压作用。阿托品可阻断中枢性降压作用。此作用位于中枢神经系统内，但并不意味着酮色林对中枢神经系统毒蕈碱受体有直接影响。
