Structural and functional organization of the cerebral cortex neurons in rats with various resistance to emotional stress following administration of delta-sleep-inducing peptide

In Wistar rats with different resistance to emotional stress (ES), subjected to stress exposure (SE), the structural organization of neurons in layer V of sensomotor cortex was studied quantitatively in brain sections stained using Nissl's cresyl violet method. One group of animals was injected with delta sleep-inducing peptide (DSIP) 1 hr before SE. In rats of control group predisposed to ES, the amount of normochromatic and moderately hypochromatic neurons was decreased as compared to the rats resistant to ES. After SE, normochromatic neurons were not demonstrated. In rats predisposed to ES, the contents of moderately hypo- and hyperchromatic neurons was found to fall dramatically with a simultaneous increase in the number of extremely hypo- and hyperchromatic neurons, ghost cells and ischemically changed cells. After DSIP infusion before SE, ischemically damaged cells were not found in any group, while the degree of shrinkage of extremely hyperchromatic neurons was lower in rats predisposed to ES as compared to rats resistant to ES. It is suggested that brain hypoxia plays an important role in cortex disorganization during ES, whereas DSIP, possesses both antistress and antihypoxic effects.