Changes of Neuropeptides in the Basal Ganglia of Hemiparkinsonian Rat Model

ABSTRACT

We used in situ hybridization histochemistry with synthetic oligonucleotide probes to examined the effects of unilateral 6-hydroxydopamine lesions (which eliminated tyrosine hydroxylase mRNA containing cells in mesencephalon) on enkephalin, dynorphin, and substance P mRNA exprssion in the striatum. The expression of tyroxine hydroxylase mRNA on ipsilateral substantia nigra pars compacta, which reflect dopamine activity, totally decreased for 2weeks after lesioning. After lesioning 1week, 2weeks, and 4weeks, a significant increase of the expression of enkephalin mRNA in ipsilateral to the lesioned striatum was observed (p<0.05). Substance P mRNA expressions were depressed significantly in ispsilateral to the lesioned striaturm, whereas enkephalin mRNA expressions were elevated in consecutive sections from striatal aresas in all rat model. The effect of lesions on dynorphin mRNA expressions in ipsilateral to the lesioned striatum less robust, but significant decreased tendency was observed (p<0.05). These data show that the expression of enkephalin, dynorphin and substance P mRNA is differentially regulated by mesostriatal dopaminergic system.