Effects of lithium chloride administered in combination with methamphetamine or a reserpine- like drug on brain norepinephrine and dopamine metabolism in rats

Abstract

Lithium chloride (LiCl) was injected acutely (2.4 mEq/kg, i.p.) or subacutely (2.5 mEq/kg X 2/day for 4.5 days, i.p.) in rats treated concurrently with methamphetamine (MAPT) or a reserpine-like drug (Ro4-1284), and effects of LiCl on behavior as well as metabolism of brain norepinephrine (NE) and dopamine (DA) were investigated. Acute administration of LiCl suppressed the MAPT-induced hyper-locomotor activity but did not affect the Ro4-1284-induced behavioral depression. LiCl administered subacutely increased the MAPT-induced stereotyped behavior, and it reduced the Ro4-1284-induced initial transient excitation in spontaneous locomotor activity and tended to facilitate the recovery from behavioral depression. As for NE and DA metabolism, LiCl administered subacutely inhibited the MAPT-induced decrease of the deaminated NE metabolites and Ro4-1284-induced decrease of DA metabolism and the Ro4-1284-induced alterations in NE metabolism. From these results, it is likely that the inhibitory effect of LiCl on the MAPT and Ro-1284-induced changes in NE and DA metabolism may to some extent be involved in the therapeutic effects on manic-depressive illness.