Abstract
The effects of prenatal stress (PNS) on the formation of the orexinergic and dopaminergic systems of the brain were studied in 14- and 30-day-old rat pups born to females subjected to sleep deprivation (6 h/day) using the “small areas” method from day 13 to day 19 of pregnancy. The open fi eld test showed impairments to motor development in 14-day-old PNS rat pups. Immunohistochemical studies of brain sections showed that the hypothalamus contained a signifi cantly larger quantity of orexin A in neurons in the periforniceal area, while high-performance liquid chromatography demonstrated increases in the dopamine level and its rate of metabolism as compared with control rat pups born to intact females. Western blotting results provided evidence of a decrease in the striatal level of the GABA-sythesizing enzyme (GAD65) and an increase in the level of tyrosine hydroxylase (an enzyme involved in dopamine synthesis) phosphorylated at serine-40 as compared with controls. By day 30 of life measures of motor activity in PNS rat pups were no different from those in controls, though PNS rat pups had higher levels of anxiety and lower levels of exploratory activity. The results of morphological and biochemical studies also provided evidence that there were no differences between the study parameters in the hypothalamus and striatum in 30-day-old rat pups as compared with controls, which was confi rmed by results from electrophysiological studies indicating that there were no differences in the organization of the sleep-waking cycle in 30-day-old PNS and control rat pups. We discuss here the morphofunctional interactions of the orexinergic and dopaminergic systems of the brain in the early postnatal period of development of the body and the role of orexins in the compensatory mechanisms of the brain.
Published Version
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