The GAbAergic and cholinergic systems in the retina are differentially affected by postnatal malnutrition during the...

Malnutrition by severe protein deprivation induces deleterious consequences in the nervous system particularly in the initial period of development. These deficits can alter several important events during development, such as the expression of neurotransmitters. The induction of nutritional deficiency by using low protein diet, similar to that consumed by low income populations in Brazil, was applied in rats to investigate the effect of malnutrition on cells containing gamma-aminobutyric acid (GABA) and acetylcholine in the retina. GABA immunoreactivity was present in cells in the inner nuclear and ganglion cell layers and in processes in the inner and outer plexiform layers in retinas of control and malnourished animals. At postnatal day 8, there is a decrease (ca. 40%) of the GABAergic neurons in malnourished animals. At P13 and P21 the percentage of these neurons increased and was equivalent to control animals in the adult. Glutamic acid decarboxylase activity did not show significant changes between the two groups along development. Choline acetyltransferase immunoreactivity was localized in amacrine cells in the inner nuclear and ganglion cell layers and their processes in the inner plexiform layer. The percentage of cholinergic cells was always higher in malnourished animals than that observed in the control until postnatal day 30, when the same proportion of cholinergic neurons was found in the retinas of both groups. Choline acetyltransferase activity did not show significant changes between the two groups along development. In conclusion, our results show that despite the extreme somatic and behavioral changes observed the neurotransmitter systems studied were at a certain extent shielded from the insult.