Distribution of muscarinic receptors on cultured myenteric neurons.

The distribution of neurotransmitter receptors over the neuronal cell surface remains an outstanding question in neurobiology. In this study we have used autoradiographic procedures to localize muscarinic receptors on living cultures of enteric neurons, using the specific irreversible muscarinic ligand, [3H]propylbenzilylcholine mustard ([3H]PrBCM). Most of the label was associated with nerve processes surrounding the cell bodies and along the lengths of many of the neurites radiating from the cell bodies; a small proportion of the nerve cell bodies was also seen to be labeled. The distribution of autoradiograph silver grains along both varicose and non-varicose neurites demonstrated that muscarinic receptors were present on both pre-terminal and terminal regions of the nerve fibres.