Neurohormonal changes during formation of latent inhibition in rats predisposed to catalepsy

The response of two monoaminergic systems to induction of latent inhibition has been studied in two rat strains. The noradrenergic system of the Wistar rat brain responded uniformly and systemically in the hippocampus, hypothalamus, amygdala, and frontal cortex. It has been shown that footshock induced a decrease in the norepinephrine level and the return of the mediator level to the control level in the “adaptation + footshock” groups for the four brain regions studied. Significant differences in norepinephrine levels were found in the “footshock” group in the hippocampus and hypothalamus of Wistar rats but not GC rats. The lowest serotonin level in the hippocampus was found in the “adaptation + footshock” group of the cataleptic strain. Opposite changes in corticosterone levels in the blood plasma of GC and Wistar rats were significant according to the F test (F[2, 70] = 3.908, p < 0.05). Differences in the testosterone levels between the two strains during induction of the latent inhibition were absent.