Ethanol effects on striatal dopamine receptor-coupled adenylate cyclase and on striatal opiate receptors

The perturbation of neuronal cell membranes by ethanol may result in specific functional changes through modification of the activity of various membrane-bound proteins. In mouse striatum, adenylate cyclase, a membrane-bound enzyme, is coupled to dopamine, as well as to opiate, receptors. Ethanol stimulates striatal adenylate cyclase activity by modifying the regulatory protein ("G-protein")-adenylate cyclase interaction to produce an increased amount of activated enzyme. This action is additive with the effects of dopamine on adenylate cyclase. Ethanol also modifies striatal opiate receptor-effector coupling processes. In the presence of ethanol, opiate receptor affinity is altered, and this alteration is modified by GTP, suggesting that ethanol influences the interaction of the opiate receptor complex with the G-protein. Our results suggest that ethanol can affect receptor-effector coupling, including the binding of opiate agonists to their receptors, through its membrane-disordering capacity, and that particular systems may react in a relatively specific manner with ethanol.