Reserpine-induced changes in dopamine-beta-hydroxylase activity in the terminal projections of the nucleus locus coeruleus.
Rats received daily subcutaneous injections of reserpine (2.5 mg/kg) for 3 days. Dopamine-beta-hydroxylase (DBH) activity was measured in the dorsal pons (which contained the locus coeruleus), cerebellum, hippocampus and frontal cortex 1, 2 and 4 weeks after the last injection. In accordance with previous reports, reserpine significantly increased DBH activity in dorsal pons 1 and 2 weeks after reserpine. In the other brain regions, which contain noradrenergic terminals of the locus coeruleus, reserpine either produced no change in DBH activity (cerebellum) or resulted in significant decreases in enzyme activity 1-4 weeks after the last injection (hippocampus and frontal cortex). Induction of DBH in the locus coeruleus is not, therefore, subsequently reflected in an overall increase in enzyme activity in the terminals arising from this nucleus; on the contrary, reserpine produces long-term decreases in DBH activity in these regions.
Brooke
S M
SM
Division of Neurological Sciences, Department of Psychiatry, University of British Columbia, Vancouver, B.C., V6T 1W5, Canada.
Fibiger
H C
HC