Characterization of alpha-adrenergic receptors in guinea pig cerebral cortex: effect of chronic antidepressant treatments.

Alpha-adrenergic receptor sites in cerebral cortex membranes of the guinea pig have been characterized by the specific binding of 3H-WB4101, an alpha-adrenergic antagonist. The binding was rapid, reversible, saturable, and stereoselective. The maximal binding site (Bmax) and dissociation constant (kd) for 3H-WB4101 were calculated to be 251 fmol/mg protein and 1.23 nM, respectively. Ligand displacement experiments suggest that 3H-WB4101 binds to alpha 1-adrenergic receptors. Chronic treatment of guinea pigs with desipramine, amitriptyline, phenelzine, or electroconvulsive shock failed to show any statistically significant change in alpha-adrenergic receptor sensitivity as measured by the binding of 3H-WB4101.