RESUMO
The effects of severe protein malnutrition (4%) on myenteric neurons of Wistar rat duodenum, in relation to a standard 22%-protein diet for rodents, were assessed in this study. Segments of the duodenum from 10 rats from each nutritional group were submitted to the elaboration of whole mounts - 5 stained with Giemsa to determine the total population of myenteric neurons and the others stained by a histochemical method to detect nervous cells through the NADPH-diaphorase enzyme activity for studying the subpopulation of nitrergic neurons. The area of 100 neurons per animal, totalizing 2,000 neurons, were randomly measured by using the Image Pro-Plus(®)software. Malnourished rats presented 34.38% lower body weight and 10.60% duodenum length reduction when compared to the control group. Quantitative analysis demonstrated no significant differences between control and malnourished group by using Giemsa; however, as the organ reduction was not followed by an increase inversely proportional to the density of neurons, the condition imposed suggests the loss of neurons from the total population. Nevertheless, through NADPH-d histochemistry, there was a neuronal density increase for the malnourished group. There was no significant difference between the groups for both techniques with respect to the morphometric analysis of the body cell.