Modulation of alpha-1 adrenergic receptors in rat brain following chronic reserpine

Functional denervation of the central adrenergic receptors by 30 daily injections of reserpine (0.25 mg/kg/day s.c.) produced an increase in the B(max) of alpha-l adrenergic receptor binding sites labeled by [(3)H]prazosin. A similar increase was also observed for the alpha-1 adrenergic receptor component of [(3)H]WB4101 binding in the hippocampus but not in the cortex. No change in the lower affinity [(3)H]WB4101 binding site, which identifies S-l serotonin receptors was detected after this treatment. These data support the hypothesis that alpha-1 receptors are regulated by their neurotransmitter and may explain why previous studies have not detected alpha-1 receptor increases following 6-hydroxydopamine lesions of the dorsal bundle and locus coeruleus.