Abstract: | According to various suggestions in the literature of cholinomimetic effects of carnitine on nervous structures, and experimental results of previous work on vascular smooth muscle, we studied the influence of this substance on the rat isolated and denervated stomach responses to acetylcholine (Ach). We found that Ach invariably induces contraction of the preparation, this effect being abolished by means of atropine or prifinium bromide or reduced by means of fendiline or flunarizine. We found also that carnitine invariably enhances the contractile responses of the preparation to Ach, and this effect is not modified by indomethacin or lysine acetylsalicylate, but usually abolished by fendiline and flunarizine. Our opinion is that the potentiation of stomach contractile responses to Ach by carnitine, is not due to prostaglandin mediation but it is due to sensitisation of the muscarinic receptors, which are stimulating contraction (here and in vascular smooth muscle) by means of: facilitation of calcium transit across the cellular membrane; intracellular deposit site release activation. |