Evidence for the presence of P2y and P2x receptors with different functions in mouse stomach.
To clarify the function of P2 receptor subtypes in mouse stomach, the motor responses to ATP, alpha,beta-methyleneATP (alpha,beta-MeATP), P2X receptor agonist, 2-methylthioATP (2-MeSATP), P2Y receptor agonist, and the effects of the desensitisation of P2X receptors with alpha,beta-MeATP and of P2Y receptors with ADPbetaS were analysed recording the endoluminal pressure from whole-organ. ATP-induced relaxation was antagonised by suramin, non-selective P2 receptor antagonist, by desensitisation of P2Y receptors with ADPbetaS, and increased by desensitisation of P2X receptors with alpha,beta-MeATP. alpha,beta-MeATP produced biphasic responses: relaxation, reduced by P2X- or P2Y desensitisation, and contraction, almost abolished by P2X desensitisation and potentiated by P2Y desensitisation. 2-MeSATP induced relaxation, which was antagonised by P2Y desensitisation and increased by P2X desensitisation. Tetrodotoxin increased the relaxation induced by purines and deeply antagonised the contraction to alpha,beta-MeATP. Our results suggest that in mouse stomach are present muscular P2Y receptors, subserving relaxation, and neuronal presynaptic P2X receptors, mediating contraction.
Mulè
Flavia
F
Dipartimento di Biologia cellulare e dello Sviluppo, Laboratorio di Fisiologia generale, Università di Palermo, Italy. fmule@unipa.it
Naccari
Davide
D
Serio
Rosa
R
D000244:Adenosine Diphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D058469:Receptors, Purinergic P2X; D013270:Stomach / Q000187:drug effects / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology
D018048:Receptors, Purinergic P2; D058469:Receptors, Purinergic P2X; D013873:Thionucleotides; C030812:adenosine 5'-O-(2-thiodiphosphate); D013779:Tetrodotoxin; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; C008501:2-methylthio-ATP