百日咳毒素增强异丙肾上腺素诱导的离体回肠的舒张作用。
Pertussis toxin increases isoproterenol induced relaxation in field-stimulated ileum.
作者信息
Sawyer G, Ehlert F
机构信息
Department of Pharmacology, College of Medicine, University of California, Irvine 92697, USA.
出版信息
Eur J Pharmacol. 1999 Feb 12;367(1):81-4. doi: 10.1016/s0014-2999(99)00002-3.
We investigated the effects of pertussis toxin on contraction in field-stimulated guinea pig ileum in the absence and presence of isoproterenol. Field-stimulation elicited pertussis toxin-insensitive contractions. Cumulative addition of isoproterenol produced a maximal 52% reduction in the contractile response. Following pertussis toxin-treatment, the maximal inhibitory effect of isoproterenol increased to 83%. Pertussis toxin had no effect on the ability isoproterenol to inhibit contractions elicited by histamine agonists. Our results suggest that the increased effectiveness of isoproterenol in pertussis toxin-treated ileum is due to an uncoupling of the muscarinic M2 receptor contractile mechanism.
我们研究了百日咳毒素在有无异丙肾上腺素存在的情况下对豚鼠离体回肠场刺激收缩的影响。场刺激引发了百日咳毒素不敏感的收缩。异丙肾上腺素的累积添加使收缩反应最大降低了52%。百日咳毒素处理后，异丙肾上腺素的最大抑制作用增加到83%。百日咳毒素对异丙肾上腺素抑制组胺激动剂引发的收缩的能力没有影响。我们的结果表明，在百日咳毒素处理的回肠中异丙肾上腺素有效性的增加是由于毒蕈碱M2受体收缩机制的解偶联。
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