L. Xue et al., ATP is a mediator of the fast inhibitory junction potential in human jejunal circular smooth muscle, AM J P-GAST, 39(6), 1999, pp. G1373-G1379
Citations number
25
Categorie Soggetti
da verificare
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY
The neurotransmitter(s) that generates the fast component of the inhibitory
junction potential (IJP-F) in human jejunal circular smooth muscle is not
known. The aim of this study was to determine the role of ATP and purinergi
c receptors in the generation of the IJP-F in human jejunal circular smooth
muscle strips. The P-2-receptor antagonist suramin (100 mu M) reduced the
IJP-F by 28%. Apamin (1 mu M) reduced the IJP-F by 25%. Desensitization of
muscle strips with the putative P-2x-receptor agonist alpha,beta-methylene
ATP (alpha,beta-MeATP, 100 mu M) decreased the IJP-F by 44%, and desensitiz
ation with the putative P-2y-receptor agonist adenosine 5'-O-2-thiodiphosph
ate (ADP beta S) completely abolished the IJP-F. Desensitization with the p
utative P-2y-receptor agonist 2-methylthioATP had no effect on the IJP-F. E
xogenous ATP evoked a hyperpolarization with a time course that matched the
IJP-F. The ATP-evoked hyperpolarization was reduced by apamin and suramin,
reduced by desensitization with alpha,beta-MeATP (69% decrease), and aboli
shed by desensitization with ADP beta S. These data suggest that the IJP-F
in human jejunal circular smooth muscle is mediated in part by ATP through
an ADP beta S-sensitive P-2 receptor.