Reconstitution of alpha 1-adrenoceptors having high affinity for prazosin.
Using a variety of detergents we find that soluble alpha 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 1-adrenoceptors solubilized in sodium cholate were reconstituted into brain lipids. Specific [3H]prazosin binding to the reconstituted receptor was saturable and of high affinity (KD = 0.019 +/- 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.
Valliere
J E
JE
Department of Pharmacology, Vermont Center for Vascular Research, University of Vermont, Burlington 05405.
DeLuca
A W
AW
Shreeve
S M
SM
D000818:Animals; D001011:Aorta / Q000378:metabolism; D002417:Cattle; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism; D008563:Membrane Lipids / Q000378:metabolism; D008861:Microsomes / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000378:metabolism; D011224:Prazosin / Q000378:metabolism*; D011869:Radioligand Assay; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*
D008563:Membrane Lipids; D011942:Receptors, Adrenergic, alpha; D011224:Prazosin