Identification of cholinoreceptors on the soma of snail neurons RPa3 and LPa3

Identification of cholinoreceptors (CR) of the soma of neurons RPa3 and LPa3 of the snail is performed using selective cholinomimetics and cholinolytics during the recording of transmembrane ionic currents. Agonists of the nicotinic (NCR) and muscarinic (MCR) types of cholinolytics evoked a brief activation of the receptors, with the exception of carbamylcholine, followed by an irreversible blocking. All selective cholinomimetics bonded with the same membrane centers which acetylcholine (AC) activated. The nicotinic and muscarinic cholinolytics decreased the amplitude of the input current elicited by AC; however, the use of scopolamine and platyphylline was without effect. It is speculated that the soma of neurons RPa3 and LPa3 exhibits NCR and MCR which have a number of pharmacological features distinguishing them from the corresponding CR of vertebrates. The MCR of these neurons must be classed as a special subtype differing from the well-known M₁ and M₂ subtypes.M. V. Lomonosov State University of Moscow. Translated from Neirofiziologiya, Vol. 24, No. 1, pp. 77–86, January–February, 1992.