Subunit Composition of Nicotinic Acetylcholine Receptors in Neurons of the Rat Intracardiac Ganglia

The effect of the antibodies against α3, α4, α5, and α7 subunits of neuronal nicotinic acetylcholine receptors (nAChR) on ACh-induced shifts of the membrane potential (ACh potentials) in neurons of the intracardiac ganglia of the rat left atrium was studied using intracellular electrodes. It was found that (i) antibodies against each of the above subunits caused only a partial block of ACh potential; (ii) the blocking effect of each particular antibody could be observed only in some of the examined neurons; (iii) in all neurons under study the block caused by a single antibody was only partial; (iv) the blocking effects of two or more antibodies on the ACh potential recorded from the same neuron were additive. It was concluded that (1) each of the above nAChR subunits is present only in a part of the intracardiac neurons, and (2) each intracardiac neuron has nAChR composed of more than one α subunit.