The function of the hippocampus declines with the ongoing accumulation of biochemical wear and tear in the body. As for so many aspects of aging, calorie restriction makes some modest difference here: "Caloric restriction (CR) extends life span and ameliorates the aging-related decline in hippocampal-dependent cognitive function. In the present study, we compared subunit levels of NMDA and AMPA types of the glutamate receptor ... Each of these parameters has been reported to be a potential contributor to hippocampal function. Western blot analysis revealed that NMDA and AMPA receptor subunits in [ad libitum (AL)] animals decrease between young and middle age to levels that are present at old age. Interestingly, young CR animals have significantly lower levels of glutamate receptor subunits than young AL animals and those lower levels are maintained across life span. ... These results indicate significant aging-related losses of hippocampal glutamate receptor subunits in AL rats that are consistent with altered synaptic function. CR eliminates that aging-related decline by inducing stable NMDA and AMPA receptor subunit levels."