The effect of neurochemical damage of dopaminergic terminals in early ontogenesis on the behavior of adult rats

摘要

6-Hydroxydopamine (75 mkg), producing selective degeneration of dopaminergic neurons in the brain, was injected intraamniotically to every rat fetus on 13th or 17th day of mother pregnancy. The other experiment was performed, when 6-hydroxydopamine administered i.p. to newborn rats on 4th or 10th day of life. All rats were growing, and several dopamine-dependent behaviors were investigated in adult animals: open field, rotation behavior, anxiety in elevated plus maze, conditioned placed preference, differentiation of novel and known alleys of Y-maze, aggressive behavior in intruder-resident test, selfs-stimulation of lateral hypothalamus. Prenatal administration of 6-hydroxydopamine initiated rotations and stereotypy, decreased anxiety in elevated maze, reduced reinforcing properties of amphetamine in place preference test, disturbed differentiation of novel and known alley in Y-maze, high aggression and decreased self-stimulation in less degree that postnatal injection of neurotoxin. Therefore, the early postnatal period is more sensitive to neurotoxin action than prenatal period of development. This phenomenon is connected with critical periods of development of dopaminergic system in ontogeny.