The tripeptide, L-prolyl-L-leucyl-glycinamide (PLG) has been shown to facilitate dopaminergic mechanisms in the brain. In the present study, we evaluated the interaction of PLG and its synthetic analogs with levodopa in two animal models of Parkinson's disease. In one experiment using rats with chronic unilateral lesions of the nigrostriatal dopamine pathway, PLG and Z-PLG potentiated the contraversive rotation elicited by levodopa with carbidopa (L/C). In a second experiment using reserpinized rats, PLG, Z-PLG and cyclo-LG potentiated L/C reversal of hypokinesia. Further studies of the PLG analogs, Z-PLG and cyclo-LG as adjunctive drugs with levodopa in the treatment of parkinsonism are warranted.
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Pharmacology, Toxicology and Pharmaceutics(all)