Muscarinic cholinergic receptor binding in bovine retina

Using [³H] quinuclidinyl benzylate ([³H] QNB) muscarinic cholinergic receptors have been demonstrated in crude membrane fractions of bovine retina. Specific [³H] QNB binding is saturable with a K_D of 0.5 nM and a maximal number of muscarinic agonists and antagonists for displacing specific [³H] QNB binding closely parallel the affinities for muscarinic receptors in rat brain and guinea pig ileum. The findings may explain atropine sensitive effects of muscarinic agonists on the electroretinogram and on retinal cells in vitro.