Muscarinic receptor binding in the rat adrenal medulla.

Muscarinic receptor binding sites are present in rat adrenal gland andare associated primarily with the medulla. A Scatchard analysis using the ligand [3H]-quinuclidinyl benzylate (eH-QNB) revealed a KD of 0.064 nM and a Bmax of 66 fmol/mg prot. Denervation of the adrenal gland had no significant effect on 3H-QNG binding. The presence of muscarinic receptor binding sites in the adrenal medulla is consistent with reports that muscarinic receptors play a role in the release of adrenal catecholamines and modulation of cycle 3',5'-guanosine monophosphate.