THE BINDING-PROPERTIES OF THE MUSCARINIC RECEPTORS OF THE CYNOMOLGUS MONKEY CILIARY BODY AND THE RESPONSE TO THE INDUCTION OF AGONIST SUBSENSITIVITY

The binding properties of the muscarinic receptors in the ciliary muscle of cynomolgus monkeys were evaluated. The concentration of receptor binding sites is the highest yet reported. As found in many species and tissues, there are subclasses of agonist binding sites. Agonist binding [pirenzepine, carbachol and pilocapine] is not affected by the non-hydrolyzable (GTP) analog, GppNHp, suggesting that these receptors are not linked to adenylate cyclase. Ciliary muscles made subsensitive by treatment with muscarinic agonists have a decreased receptor concentration but no other changes in the binding properties of the receptors could be detected. [The radiologand used [3H]-N-methylscopolamine, a potent muscarinic antagonist.].