Cyclic AMP and beta-adrenergic receptors during the development of physical dependence on ethanol in the rat.

1. The half-time for maximal withdrawal scores in the rat is 30 to 36 hours following around the clock intubation with ethanol. 2. Cyclic AMP levels in all brain areas decline with ethanol treatment and rise again to control levels during withdrawal. 3. Norepinephrine-stimulated adenylate cyclase activity is increased by chronic treatment with ethanol. However, it is unlikely that this change is related to physical dependence, as it occurs 50 to 60 hours following the development of half-maximal withdrawal scores. 4. Ethanol had no effect on the concentration of beta-receptors in the cerebral cortex.