Effect of D-amphetamine on dopaminergic neurons of substantia nigra and expression of tyrosine hydroxylase in striatum and pre-frontal cortex of D-amphetamine treated Wistar rats

Abstract

Dopaminergic neurons of the midbrain are the main source of dopamine in the mammalian central nervous system. Dopamine is a chemical messenger active in mesolimbic and mesocortical reward pathways. Dopamine is manufactured in nerve cell bodies in the ventral tegmental area (VTA) and is released in the nucleus accumbens and the prefrontal cortex. The objective was to compare dopaminergic neurons of substantia nigra and level of tyrosine hydroxylase (TH) in the striatum and pre-frontal cortex of D-amphetamine treated wistar mice. 15 Wistar rats were injected subcutaneously with amphetamine 10 mg/kg body weight till 7 days while the controls groups (15 wistar rats) were injected with normal saline in the same dose. One way-ANOVA test and Post-hoc tests was applied and decreased level of tyrosine hydroxylase was present in striatum (65%) and pre-frontal cortex (71%). The percentage of tyrosine hydroxylase in all these areas were highly significant (p<0.001). D-AMPH affects the neuronal cell morphology and decreases expression level of Tyrosine hydroxylase. Degeneration of dopaminergic neurons and damaged synaptic connection in substantia nigra were observed leading to a reduction of stratial dopamine levels.