title: Developmental change of beta-adrenergic receptors in rat brain.
abstract: The developmental change of beta-adrenergic receptors in rat whole brain, except the cerebellum, was studied by binding assays with (--) 3H-dihydroalprenolol. The synaptic membrane fraction, prepared from 2-day-old and 6-week-old rat brains, had binding sites for (--) 3H-dihydroalprenolol, which seemed to represent physiological beta-adrenoceptors. The maximal binding capacity and the dissociation constant for (--) 3H-dihydroalprenolol of the synaptic membrane fraction did not vary with the age of the rats, but the yield of synaptic membrane fraction from the brain of 2-day-old rats was much less. Therefore, the total number of binding sites was less in 2-day-old rats. In addition, there was a significant difference in the inhibitory effects of 1-isoproterenol on binding of (--) 3H-dihydroalprenolol to the synaptic membrane fractions in the 2-day as compared to the tissues from the 6-week-old animals. The developmental changes in the number and nature of beta-adrenoceptors may result in expression of catecholamine-sensitive adenylate cyclase activity.
mesh_terms: D000367:Age Factors; D000818:Animals; D001665:Binding Sites; D001923:Brain Chemistry; D004082:Dihydroalprenolol / Q000378:metabolism; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D051381:Rats; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D013570:Synaptic Membranes / Q000378:metabolism
chemical_list: D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D004082:Dihydroalprenolol; D007545:Isoproterenol