Effect of L-threo-3,4-dihydroxyphenylserine (L-DOPS) on catecholamine levels in plasma and cerebrospinal fluid (CSF) in anesthetized rats.

The effect of L-threo-3,4-dihydroxyphenylserine (L-DOPS) on norepinephrine (NE) levels in plasma and CSF was examined in urethane-anesthetized rats. Intravenous injection of L-DOPS (0.5, 1, and 10 mg/100 g body wt) raised plasma NE levels in a dose-related manner whereas CSF NE levels were significantly increased only by the largest dose of L-DOPS. Intracerebroventricular injection of L-DOPS (50 and 250 micrograms/rat) dose-relatedly raised CSF NE levels whereas plasma NE levels were slightly increased by a larger dose of L-DOPS. These findings may indicate that L-DOPS stimulates central noradrenergic mechanisms in the rat although a large dose of L-DOPS is required for peripheral administration.