Erowid References Database
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Dolphin A, Adrien J, Hamon M, Bockaert J.
“Identity of (3H)-Dibydroalprenolol Binding Sites and p-Adrenergic Receptors Coupled with Adenylate Cyclase in the Central Nervous System: Pharmacological Properties, Distribution and Adaptive Responsiveness”.
Molec.Pharmacol.. 1979;15(1):1 - 15.
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Abstract
The binding of (-)-3H dihydroalprenolol (3H-DHA) and p adrenergic-sensitive adenylate cyclase were measured in particulate fractions from brain. Reserpine, (2.5 mg/kg on the 1st day and 0.5 mg/kg on 3 following days) and + propranolol (Sigma-Chem. 10 mg/kg t.i.d.) chlorpromazine (Rhone-Poulenc, 5, 10 or 20 mg/kg) or phenoxybenzamine, (SK+F 10 mg/kg) daily for 7 days were given i.p. to male Charles River rats (200-300 g).6-hydroxydopamine (6 OHDA, Regis 1 mg free base) was injected bilaterally into the frontal horns of the lateral ventricles of 5 day-old cats. 3H-DHA Receptor binding and isoprenaline-sensitive adenylate cyclase activity in the cerebral cortex were measured. 3H-DHA interacted with a single category of binding sites in rat cerebral cortex and competitively inhibited the (-) isoproterenol sensitive adenylate cyclase. The similarity between affinity for 3H-DHA binding sites and adenylate cyclase inhibition was true for DHA (-)-isoproterenol (Sigma-Chem.), protokylol (Lakeside), (-)-norepinephrine, (-)-epinephrine, () isoproterenol (all Sigma-Chem.), (-)alprenolol (ClBA-Geigy), (+)-LSD (Sandoz) (-) and (+)-propranolot practolol (both ICI) and salbutamol (Allen and Hanbury's). The (-)-stereoisomers were more potent than (+)-stereoisomers. Phentolamine (CIBA Geigy) and phenoxybenzamine were inactive, while chlorpromazine had a very low affinity for 3H-DHA binding sites and antagonism of isoproterenol sensitive adenylate cyclase. The distribution of 3H-DHA binding sites and p-adrenergic sensitive adenylate cyclase were correlated in both cat brain and rat cerebral cortex. Chronic reserpine propranolol or 6-OHDA administration caused a signifi cant increase in the number of 3H-DHA binding sites and in isoprenaline-stimulated adenylate cyclase activity, but phenoxybenzamine or chlorpromazine had no effect, No changes were seen in basal adenylate cyclase activity, or in the affinity of 3H-DHA for its binding sites or of (-)-isoproterenol for the activation of adenylate cyclase.
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