Wiklund N P, Gustafsson L E
Department of Physiology, Karolinska Institute, Stockholm, Sweden.
Eur J Pharmacol. 1988 Apr 13;148(3):361-70. doi: 10.1016/0014-2999(88)90114-8.
The effects of ADP, ATP, 2-methylthio ATP, alpha,beta-methylene ADP (alpha,beta meADP) and alpha,beta meATP on smooth muscle tone and the responses to transmural nerve stimulation were studied in isolated longitudinal ileum muscle, in vas deferens and in taenia coli of the guinea pig. The nucleotides evoked contractile responses in the ileum and vas deferens preparations which were blocked by p-chloromercuribenzene sulfonic acid (PCMBS) and evoked relaxation in the taenia which was not affected by PCMBS. The potency order of the agonists in the ileum (2-methylthio ATP was more potent than ATP which was equipotent with ADP) is consistent with the suggestion that there are P2Y receptors in the taenia. The antagonist pattern, including the inefficacy of reactive blue 2, instead suggests a similarity between the ileum receptors and the P2X receptors in vas deferens. However, alpha,beta meATP did not antagonize the contractile effect of ATP in the ileum, in contrast to its effect in the vas deferens where alpha,beta meATP did abolish the contractile effect of ATP. The possibilities for classification of a new receptor/site of purine nucleotide action, P2S, are considered.
在豚鼠离体纵行回肠肌、输精管和结肠带中，研究了二磷酸腺苷（ADP）、三磷酸腺苷（ATP）、2-甲硫基三磷酸腺苷、α,β-亚甲基二磷酸腺苷（α,β meADP）和α,β-亚甲基三磷酸腺苷（α,β meATP）对平滑肌张力及对跨壁神经刺激反应的影响。这些核苷酸在回肠和输精管标本中引起收缩反应，此反应可被对氯汞苯磺酸（PCMBS）阻断；而在结肠带中引起松弛反应，且不受PCMBS影响。激动剂在回肠中的效价顺序（2-甲硫基三磷酸腺苷比三磷酸腺苷更有效，三磷酸腺苷与二磷酸腺苷等效）与结肠带中存在P2Y受体的推测一致。然而，拮抗剂模式，包括活性蓝2无效，反而提示回肠受体与输精管中的P2X受体相似。但是，与α,β meATP在输精管中能消除三磷酸腺苷的收缩作用相反其在回肠中并不能拮抗三磷酸腺苷的收缩作用。文中还考虑了嘌呤核苷酸作用新受体/位点P2S的分类可能性。
