Morphometric and histochemical characteristics of the neocortex and hippocampus of experimentally enlarged rat brain during the suckling period of ontogeny.

Enlargement of the brain weight was attained in rats by reducing the number of neonates in the litter. The brain of 14- and 30-day-old animals was examined (controls: intact animals from litters of average numbers). Difference between the brain weight at 14 and 30 days was about 200 mg.

Association of brain weight value with morphometric and histochemical properties of cortical neurons and higher nervous activity parameters in rats in prepubertal period.

We compared thickness of the neocortex, morphometric and histochemical characteristics of neurons in frontoparietal and parietal lobes and hippocampal field I in animals from great litters with lower brain weight (group 1) and from small (artificially reduced) litters with higher brain weight (group 2). It was found that the thickness of the neocortex in the frontoparietal and parietal lobes does not differ in the compared groups, while the size of neuronal cytoplasm in layer II of the frontoparietal and parietal lobes and in layer V of the frontoparietal lobe in group 2 animals was lower than in group 1. Nuclei of cortical neurons in layer II of the parietal and frontoparietal lobes and in frontoparietal lobe layer V in group 2 animals were smaller than in group 1.

Effect of long-term constant illumination of female rats on the parameters of brain development in their 40-day-old progeny.

We studied the progeny from female rats exposed to constant illumination for 1 month and mated with intact males 14 days after this exposure. At the age of 40 days, the progeny from experimental rats differed from the control by lower body weight, thickness of the adrenal cortex, and diameter of convoluted seminal tubules. The weight of the brain was similar in both groups.