Low Protein Diet Consumption Antagonize the Age-associated Change in Hypothalamic GABA Receptor activity

Abstract

Amounts of dietary protein as well as the duration of its supplementation are criticalfactors that correlate with the hypothalamic GABAergic activity and immune functionduring aging. Here we evaluate the effect of low (5%) and high (40%) protein diet on thefunctional state of hypothalamic GABA receptor in the aging brain in albino rats. Longterm(LT; for 30 consecutive days) supplementation of low protein diet (LDP) retardedthe age-associated (3 to 18 months) (a) loss of both low and high affinity hypothalamicGABA receptor sensitivity and (b) increase of high affinity GABA receptor density.Short-term (ST; for 7 consecutive days) consumption of the same protein diet showedless effect than that observed under LT period. High protein diet (HPD), on the otherhand, under LT period potentiated the age-induced loss of both high and low affinityhypothalamic GABA receptor sensitivity, without any significant change in age associatedincrease in high affinity hypothalamic GABA receptor density. These results thus suggest that the age-induced changes in hypothalamic GABA receptor sensitivity and density may be (i) antagonised by long-term supplementation of LPD by restoring the age-associated loss of sensitivity of both low and high affinity and increase in density of only high affinity hypothalamic GABA receptor and (ii) augmented by long-term intake of HPD by potentiating only the age-associated loss of sensitivity of hypothalamic GABA receptor of both the affinity sites.