Edney S M, Downes H
Arch Int Pharmacodyn Ther. 1975 Oct;217(2):180-96.
Four different convulsant barbiturates and also thiopental, methohexital and pentobarbital were tested for in vitro contractor effects on rabbit jejunal segments, aortic strips and tracheal chains. The two convulsants that elicited lethal, tonic seizures in vivo contracted all three types of isolated preparation; however, two other convulsants that elicited intense but nonlethal, clonic seizures lacked contractor effect. Methohexital and pentobarbital also lacked contractor effect. In aortic strips, contractions induced by the two convulsants were not impaired by concentrations of phenoxybenzamine (10(-5) M) that blocked all contractor response to 10(-4) M norepinephrine, acetylcholine or histamine. Thiopental also contracted aortic strips but the effect differed from that of the convulsants in that it was much less intense, was partially antagonized by pretreatment with phenoxybenzamine, and was greatly potentiated by the presence of norepinephrine. Intense contractor effects, independent of adrenergic mechanisms, seem characteristic of a particular group of convulsant barbiturates; there are also similar with respect to structure, stimulant potency, and seizure pattern.
对四种不同的惊厥性巴比妥类药物以及硫喷妥钠、甲己炔巴比妥和戊巴比妥进行了测试，观察它们对兔空肠段、主动脉条和气管链的体外收缩作用。两种在体内引发致死性强直性惊厥的惊厥剂使所有三种类型的离体标本收缩；然而，另外两种引发强烈但非致死性阵挛性惊厥的惊厥剂缺乏收缩作用。甲己炔巴比妥和戊巴比妥也缺乏收缩作用。在主动脉条中，两种惊厥剂引起的收缩不受苯氧苄胺浓度（10⁻⁵ M）的影响，该浓度可阻断对10⁻⁴ M去甲肾上腺素、乙酰胆碱或组胺的所有收缩反应。硫喷妥钠也使主动脉条收缩，但该作用与惊厥剂不同，其强度要小得多，苯氧苄胺预处理可部分拮抗该作用，而去甲肾上腺素的存在可使其大大增强。强烈的收缩作用，独立于肾上腺素能机制，似乎是特定一组惊厥性巴比妥类药物的特征；在结构、刺激效力和惊厥模式方面也相似。
