Moneta N A, McDonald T J, Cook M A
Department of Pharmacology, University of Western Ontario, London, Canada.
Am J Physiol. 1997 Jan;272(1 Pt 1):G38-45. doi: 10.1152/ajpgi.1997.272.1.G38.
Isolated myenteric ganglion networks were prepared from guinea pig ileum and were used in a perifusion protocol to examine the effects of interstitial adenosine on evoked release of substance P-like immunoreactivity (SPLI). The release of SPLI evoked by elevated extracellular K+ concentration was increased in the presence of tetrodotoxin (TTX), indicating tonic inhibition of SPLI release and revealing net inhibitory interganglionic transmission. Perifusion in the presence of the adenosine A1 receptor-selective antagonist 1,3-dipropyl-8-cyclopentylxanthine enhanced evoked SPLI release, which was further enhanced in the additional presence of TTX, indicating that adenosine contributes some, but not all, of the overall inhibitory tone within the networks. In addition to neural release of adenosine per se, an additional source was investigated. Perifusion in the presence of alpha, beta-methylene-ADP plus guanosine 5'-monophosphate, which inhibits ecto-adenosinetriphosphatase (ATPase) activity, enhanced SPLI release, indicating that hydrolysis of released ATP contributes to the total interstitial nucleoside concentration and thereby to the overall inhibitory tone. It is concluded that endogenous adenosine, some of which arises from ATP metabolism, is an important contributor to the overall inhibitory tone present in myenteric ganglion networks.
从豚鼠回肠制备离体肠肌间神经节网络，并将其用于灌流实验，以研究间质腺苷对P物质样免疫反应性（SPLI）诱发释放的影响。在存在河豚毒素（TTX）的情况下，细胞外钾离子浓度升高诱发的SPLI释放增加，这表明存在对SPLI释放的紧张性抑制，并揭示了神经节间的净抑制性传递。在腺苷A1受体选择性拮抗剂1,3 - 二丙基 - 8 - 环戊基黄嘌呤存在下进行灌流，可增强诱发的SPLI释放，在额外存在TTX的情况下进一步增强，这表明腺苷在网络内的整体抑制性张力中起部分而非全部作用。除了腺苷本身的神经释放外，还研究了另一种来源。在存在α,β - 亚甲基 - ADP加鸟苷5'-单磷酸的情况下进行灌流，该物质可抑制胞外腺苷三磷酸酶（ATPase）活性，增强了SPLI释放，这表明释放的ATP水解对间质核苷总浓度有贡献，从而对整体抑制性张力有贡献。结论是，内源性腺苷（其中一些来自ATP代谢）是肠肌间神经节网络中整体抑制性张力的重要贡献者。
