Ca2+ utilization in guinea pig ileal longitudinal smooth muscle in response to a series of muscarinic agonists

46Ca uptake associated with the mechanical responses to a series of muscarinic agonists including carbachol, cis-2-methyl-4-dimethylaminomethyl-l,3-dioxolane methiodide, and three related 1,3-dioxolai~es, including full and partial agsnists, has been measured. Generally good agreement is found between the dose-response curves for 46Ca uptake and mechanical response, indicating that the processes of 46Ca entry. believed to be mediated through Ca* channels, and contractile response are closely linked. Consistent with this, partial agsnists show (relative to full agonists) a reduced 46Ca uptake. The dose-response curves for carbachol-mediated contractile response and 4Ca uptake are compared with available literature data for carbachol action in the guinea pig ileal smooth muscle iilcluding binding, depolarization, and phosphatidylinositol turnover. ROSENBERGER, L. B., et TRIGGLE, D. J. 1979. Ca* utilization in guinea pig ileal longitudinal smooth muscle in response to a series of muscarinic agonists. Can. J. Physiol. Pharmacol. 57, 1375-1 380. On mesure l'absorption de 46Ca associke aux rCponses mkaniques une skrie d9antagonistes muscariniques incluant le carbachol, le cis-2-m~thyl-4-din~kthylaminomkthyl-l,3-dioxolane mkthiodide et trois 1,3=dioxolanes apparentes. ceci comprenant des agonistes complets et partiels. On trouve gknkralement une bonne concordance entre les courbes doses-rkponses pour B'absorption de "Ca et pour la rkponse mkcanique indiquant que le processus d'entrk du 45Ca, que l'on croit Ctie mkdik par des canaux au Ca2' et la riponse contractile sont Ctroitement reliks. En accord avec ceci, des agonistes partiels montrent une absorption de 46Ca qui est rkduite comparativement aux agonistes csmplets. Les courbes doses-rCponses pour le carbachol, la rCponse contractile mCdiCe et l'absorption de 46Ca sont comparkes aux donnkes disponibles dans la littkrature se rapportant Zr l'action du carbachol sur le muscle ilCal lisse du cochon d'Inde, ceci iilcluant ies phinomknes de liaison, de dCpolarisation et de renouvellement du phosphatidylinositol. [Traduit par le journal]