Reconstitution of alpha sub(1)-adrenoceptors having high affinity for prazosin

Using a variety of detergents we find that soluble alpha sub(1)-adrenoceptor recovery from aortic and hepatic membranes is markedly enhanced if the receptor is first prelabelled with prazosin. Moreover, prelabelling prevents the reduction in prazosin affinity induced by solubilizing concentrations of digitonin, possibly by stabilizing the receptor's conformation. 20-25% of alpha sub(1)-adrenoceptors solubilized in sodium cholate were reconstituted into brain lipids. Specific ( super(3)H)prazosin binding to the reconstituted receptor was saturable and of high affinity (K sub(D) = 0.019 plus or minus 0.008 nM). We conclude that prelabelling is essential to preserve the receptor in detergents. However, once the detergent is removed brain lipids alone are able to maintain the receptor in a form with high affinity for prazosin.