Permanent and transitory morphometric changes of NADPH-diaphorase-containing neurons in the rat visual cortex after early malnutrition

We investigated the histochemical positivity to NADPH-diaphorase, which rev eals nitric oxide synthase activity, in area 17 of rats malnourished early in life, both in the post-weaning period (group M1), and in adulthood after nutritional recovering (group M2), Control pups (C1 and C2 groups) receive d ad libitum after weaning the same diets as their mothers, Rats of group M 2 were nutritionally recovered by receiving the control diet from post-nata l day 42 until adulthood. Aldehyde-fixed sections (200-mum thick) through a rea 17 were processed for NADPH-diaphorase histochemistry following the mal ic enzyme indirect method. The features of NADPH-diaphorase-containing neur ons of area 17 of malnourished young (M1) and adult (M2) rats were analyzed quantitatively in comparison to the matched groups C1 and C2, Permanent ch anges, represented by increase in the density and dendritic field areas of NADPH-diaphorase-positive cells, and transitory ones, represented by decrea sed Values of soma areas, were observed in area 17 of the M1 and M2 cases. However, some other features, such as dendritic branch angle and number of dendrites per cell in the gray matter, remained unchanged after malnutritio n. Thus, the findings indicate a possible relationship between early malnut rition and alterations in nitric oxide synthase-containing cells in the vis ual cortex. Physiological implications of these data may be related to syna ptic plasticity and refinement of developmental brain circuits. (C) 2000 El sevier Science Inc.