Alpha-bungarotoxin selectively inhibits stimulus-bound repetition in isolated frog sympathetic ganglion.

In the isolated frog sympathetic ganglion incubation with alpha-BTx until the steady state irreversibly inhibited synaptic transmission, furthermore, similarly to d-TC it selectively prevented stimulus-bound repetition (SBR) elicited by neostigmine. This finding showed that alpha-BTx binds nACh receptors were involved in the synaptic transmission and in the generation of SBR. Its binding was prevented by preincubation of the ganglia with cholinergic agonists and antagonists (receptor protection). Since alpha-BTx specifically binds only to C10-type nACh receptors, but not to C6-type nACh receptors, our results suggest that, in contrast to the mammalian and avian sympathetic ganglia, mostly C10-type nACh receptors are present in the frog sympathetic ganglia. The ability of the frog ganglion to generate SBR, furthermore, its selective inhibition by alpha-BTx may be explained by the presence of C10-type nACh receptors.