Influence of L-DOPA on rat brain depending on individual behavioral features

To cause brain dopaminergic hyperactivity in rats, L-DOPA was injected in August and Wistar rats with different basic stress reactivity and motor activity in open field ecperiments during 14 days. L-DOPA was used in the form of the drug madopar in dosage of 25,5 mg/kg of body mass daily. The indices of activity of metabolism enzymes, neuromediators and proteins: aminopeptidase, glutamatedehydrogenase, monoaminoxidase (substrate triptamine) and acetylcholinesterase were studied in sensomotor cortex, caudate nucleus, nucleus accumbens and hippocampus region. The intra- and between-line features of L-DOPA influence on rat brain have been found, being mostly pronounced in the animals with low motor activity. In these rats, changes were observed in all structures and for all enzymes, but in the group with high activity they concerned only GDH in caudate nucleus and nucleus accumbens. Hippocampus was the structure reacting to L-DOPA most actively as shoun by cytochemical indices, with reactions relating mainly to serotonergic system in August rats and to acetylcholinergic and glutamatergic systems in Wistar rats. The results demonstrate an essential role of genetically determined reactivity and motor activity in individual prognosis of resistance to stress and extreme situations.