Evidence for constitutively-active adenosine receptors at mammalian motor nerve endings

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• 作者：Timothy J. Searl ; ^{tjs026@northwestern.edu} ; Eugene M. Silinsky
• 关键词：G-protein coupled receptor ; Constitutive activity ; A1 adenosine receptor ; Neuromuscular junction ; End-plate potential ; Neurotransmitter release
• 刊名：European Journal of Pharmacology
• 出版年：2012
• 期刊代码：24_00142999
• 类别：neu
• 出版时间：15 June, 2012
• 卷：685
• 期：1-3
• 页码：38-41
• 文件大小：272 K

摘要

A study was made to determine if constitutively active adenosine receptors are present at mouse motor nerve endings. In preparations blocked by low Ca²⁺/high Mg²⁺ solution, 8-cyclopentyl-1,3,dipropylxanthine (CPX, 10-100 nM), which has been reported to be both an A₁ adenosine receptor antagonist and inverse agonist, produced a dose-dependent increase in the number of acetylcholine quanta released by a nerve impulse. Adenosine deaminase, which degrades ambient adenosine into its inactive congener, inosine, failed to alter the response to 100 nM CPX. 8-Cyclopentyltheophylline (CPT, 3 渭M), a competitive inhibitor at A₁ adenosine receptors, prevented the increase in acetylcholine release produced by CPX. At normal levels of acetylcholine release, neither adenosine deaminase nor CPX affected acetylcholine release at low frequencies of nerve stimulation in (+)-tubocurarine blocked preparations. The results suggest that a proportion of the acetylcholine release process is controlled by constitutively active adenosine receptors at murine motor nerve endings, providing the first evidence for constitutive activity of G-protein-coupled receptors that modulate the function of mammalian nerve endings.