Protein malnutrition alters the cholinergic and GABAergic systems of the hippocampal formation of the adult rat: an immunocytochemical study.

We attempted to find out if the cholinergic and GABAergic systems that regulate the hippocampal circuitries are disturbed after long periods of protein deprivation and, in the affirmative, to investigate if the changes are reversible following nutritional rehabilitation. A group of 2 month old rats fed with a low-protein diet for 12 months was compared with age-matched controls and with nutritionally rehabilitated rats. We have evaluated the length density of the cholinergic fiber network and estimated the numerical densities of the choline acetyltransferase and GABAergic immunoreactive neurons of the hippocampal formation. Our results show that prolonged malnutrition leads to a substantial, but reversible, reduction in the cholinergic innervation of the hippocampal formation and to an irreversible loss of hippocampal cholinergic and GABAergic neurons.