Brain Catecholamine Concentration during the First Week of Development in Rats

Abstract

Neonatal brain (whole brain minus cerebral hemispheres) dopamine (DA) and norepinephrine (NE) concentrations (pg/µg protein) were studied 30 min after an injection of L-DOPA methyl ester (50 mg/kg); haloperidol (1 mg/kg); D-amphetamine sulfate (0.5 mg/ kg); saline only or no treatment. Catecholamines were assayed on the day of birth (postnatal day 1) and postnatal day 7 by high performance liquid chromatography coupled with an electrochemical detector for catecholamines (CA). When L-DOPA was administered there was a selective 7x (postnatal day 1) or 3x (day 7) increase in brain DA when compared to saline controls. Haloperidol pretreatment on either day prevented these increases after L-DOPA. These findings constitute biochemical evidence for selective elevation of brain DA during the first postnatal week of life after L-DOPA administration in a dosage that is also capable of enhancing the coordination required for swimming behavior.