Cortical microvascular changes in chronological aging, cortical insults and chronic alcohol intoxication in rats. Effects of antihypoxic drug on these phenomena

Piracetam impedes hippocampal neuronal loss during withdrawal after chronic alcohol intake

In previous studies we have demonstrated that prolonged ethanol consumption induced hippocampal neuronal loss. In addition, we have shown that withdrawal after chronic alcohol intake augmented such degenerative activity leading to increased neuronal death in all subregions of the hippocampal formation but in the CA3 field. In an attempt to reverse this situation, we tested, during the withdrawal period, the effects of piracetam (2-oxo-1-pyrrolidine acetamide), a cyclic derivative of gamma-aminobutyric acid, as there is previous evidence that it might act as a neuronoprotective agent. The total number of dentate granule, hilar, and CA3 and CA1 pyramidal cells of the hippocampal formation were estimated using unbiased stereological methods. We found out that in animals treated with piracetam the numbers of dentate granule, hilar, and CA1 pyramidal cells were significantly higher than in pure withdrawn animals, and did not differ from those of alcohol-treated rats that did not undergo withdrawal. These data suggest that piracetam treatment impedes, during withdrawal, the pursuing of neuronal degeneration.

Terminal vessels of dentate gyrus in chronically alcohol-intoxicated rats

Quantitative changes in the microvasculature of the central nervous system of the rat following chronic ethanol intoxication were studied. For 6 months, 12 rats drank only 25% ethanol and eight control rats only water. After fixation by perfusion, semithin sections of dentate gyrus were obtained. In each one, semiautomatic measurements were made of the length, surface, and volume densities, and the mean area of a terminal vessel cross-section and the results were evaluated statistically. Chronic ethanol intoxication caused an increase in the length and surface density, a decrease in the mean cross-sectional area, whereas the volume density of terminal vessels was unchanged. These results show that the reduction of the mean surface area of terminal vessels after prolonged ethanol intoxication is compensated by the increase of other morphometrically measurable parameters, i.e., length and surface density. As a consequence of these alterations, the volume density remains unchanged. The results indicate great reactivity of the microvascular system of the dentate gyrus in chronically ethanol-intoxicated rats.