Handley S L, Brown J
Neuropharmacology. 1982 Jun;21(6):507-10. doi: 10.1016/0028-3908(82)90040-5.
Effects of agents with selectivity for the alpha1- or alpha2-adrenoceptor have been investigated on the head twitches induced by 5-HT injected into the cerebral ventricles in the mouse. Alpha-adrenoceptor agonists inhibited head-twitching with a rank order of potency: guanabenz, clonidine, phenylephrine, methoxamine. The antagonists yohimbine and piperoxane, potentiated the head-twitch frequency. These results suggest that there may be an involvement of an alpha2-adrenoceptor. Small doses of phenylephrine (s.c.) potentiated the head-twitch. Methoxamine, injected intracerebroventricularly potentiated the head-twitch only when alpha2-adrenoceptors were blocked by a small dose of yohimbine. Prazosin and thymoxamine inhibited the head-twitch, suggesting that alpha1-adrenoceptors also modulate this phenomenon. Yohimbine and phenylephrine increased the incidence of spontaneous head-twitches. A tonic noradrenergic input may be necessary for the occurrence of the head-twitch induced by 5-HT.
已经研究了对α1-或α2-肾上腺素能受体具有选择性的药物对小鼠脑室内注射5-羟色胺（5-HT）所诱导的头部抽搐的影响。α-肾上腺素能受体激动剂抑制头部抽搐，其效力顺序为：胍那苄、可乐定、去氧肾上腺素、甲氧明。拮抗剂育亨宾和哌泊昔烷增强了头部抽搐频率。这些结果表明可能涉及α2-肾上腺素能受体。小剂量的去氧肾上腺素（皮下注射）增强了头部抽搐。仅当小剂量育亨宾阻断α2-肾上腺素能受体时，脑室内注射甲氧明才增强头部抽搐。哌唑嗪和噻吗洛尔抑制头部抽搐，表明α1-肾上腺素能受体也调节这一现象。育亨宾和去氧肾上腺素增加了自发性头部抽搐的发生率。对于5-HT诱导的头部抽搐的发生，可能需要持续的去甲肾上腺素能输入。
