Abstract
In the isolated ileum of the guinea-pig the P2-purinoceptor antagonists PPADS and suramin: (a) strongly inhibited the cholinergic contractile effect of α,β-methylene ATP, (b) did not influence contractions evoked by exogenous acetylcholine (ACh) but, (c) moderately (by about 30%) inhibited cholinergic contractions due to electrical field stimulation (EFS), in a non-additive manner. These results suggest that an endogenous ligand that stimulates P2-purinoceptors (possibly ATP) is involved in the contractile effect of EFS, as a positive modulator of ACh release.
Keywords: P2-purinoceptors; intestine; PPADS; suramin; α,β-methylene ATP; acetylcholine release
Full Text
The Full Text of this article is available as a PDF (266.6 KB).