MUSCARINIC CHOLINERGIC RECEPTORS IN GOLDFISH RETINA

Using 3H-Quinuclinidyl Benzilate (3H-QNB) as a high affinity ligand for quantitative studies of specific binding to muscarinic cholinergic receptors we have demonstrated the presence of such receptors in homogenates of goldfish retina. Only one set of binding sites could be detected with an apparent dissociation constant of 1.9 × 10-10 M and a density of 53.5 fentomoles per mg of protein. The receptor sites become saturated at a QNB concentration of 1.2 nM. The pharmacological profile of the specific binding is similar to those described for homogenates of beef and chick retina, as well as for rodent brain and smooth muscle. © 1979.