Distribution of muscarinic receptors in the caudal cerebellum and electrosensory lateral line lobe of gymnotiform fish.

Muscarinic binding sites were found in the electrosensory lateral line lobe (ELLL) and vestibulo cerebellum (LC) of certain gymnotid fish; these binding sites were not present in significant numbers in the corpus cerebelli. Autoradiography of [3H]quinuclidinylbenzilate and [3H]propylbenzylcholine mustard binding confirmed these results and also demonstrated that, within the ELLL the region with muscarinic binding sites was coextensive with the region of cholinergic input. We did not find any evidence for nicotinic receptors (alpha-bungarotoxin binding) in ELLL, LC, or corpus cerebelli.