Apr 1, 1976

Influence of methamphetamine on nigral and striatal tyrosine hydroxylase activity and on striatal dopamine levels

European Journal of Pharmacology
F J KoganJames W Gibb

Abstract

In previous reports, methamphetamine was shown to depress tyrosine hydroxylase (TH) activity in the rat corpus striatum. To evaluate further the mechanism of this decrease in TH activity, enzyme activity was measured in the rat corpus striatum and substantia nigra after repetitive and single-dose methamphetamine administration. Following repeated doses of methamphetamine, nigral TH activity decreased and reached 45% of controls at 12 hr and returned to normal at 60 hr. Striatal TH activity decreased to 40% of control at 36 hr and returned toward normal at 60 hr. When methamphetamine was administered every 6 hr for 30 hr and then discontinued, nigral TH activity returned toward control levels 4 days prior to recovery of striatal TH activity. Methamphetamine initially increased striatal dopamine levels at 6 hr (170% of control). Dopamine levels then decreased in parallel with striatal TH activity but failed to increase as the enzyme recovered. Concurrent administration of chlorpromazine with methamphetamine prevented the methamphetamine-induced decrease in nigral and striatal TH activity and striatal dopamine levels. The results indicate that the methamphetamine-induced depression of striatal and nigral TH activity may be related...Continue Reading

Mentioned in this Paper

Depression, Chemical
Neostriatum
Hypokinesia
Entire Corpus Striatum
Lentiform Nucleus Structure
Methamphetamine Measurement
Substantia Nigra Structure
Enzyme Activity
Dopamine Measurement
Entire Substantia Nigra

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