A possible role of glutamate in the aging process

Long-term exposure of variable dietary protein-to-carbohydrate ratio: effect on brain regional glutamatergic activity with age

Glutamatergic activity of hypothalamus and hippocampus of young (3 months) male albino rats having normal diet [protein (20%)-carbohydrate (68%)] was increased with the increase of age. Long-term (60 consecutive days) feeding of low protein (8%)-high carbohydrate (80%) diet (LP-HC) increased glutamatergic activity in these brain regions of young rats and decreased that in aged (18 months). On the contrary, supplementation of high protein (50%)-low carbohydrate (38%) diet (HP-LC) under similar condition decreased glutamatergic activity in those brain regions of young and increased that in aged brain regions. Thus, prolonged exposure of LP-HC diet may damage young brain; whereas, HP-LC diet under similar condition causes excitotoxicity to aged brain. Therefore, considering the present scenario in relation to metabolism and receptor activity of glutamatergic system, it may be suggested that long-term consumption of LP-HC and HP-LC diets modulate the brain regional glutamatergic activity reversibly with age.

Is age-induced decline in immune response associated with hypothalamic glutamate receptor density and dietary protein?

Manipulation of dietary protein has been found to be the most useful dictator in the age-associated decline of neuroimmune activity in mammals. In the present study, we sought to clarify the effect of dietary protein on age-induced alterations of hypothalamic glutamatergic activity and immune response. The hypothalamic glutamatergic activity and immune response were found to increase and decrease, respectively, with the increase in age of rats from young (3 months) to old (18 months) maintained with normal (20%) protein diet. Intake of low (5%) protein diet (LPD) and high (40%) protein diet (HPD) under short-term period (7 days) failed to alter the age-associated loss of immune response and increase in hypothalamic glutamatergic activity. However, long-term (30 days) supplementation of LPD retarded the age-induced decline in immune response and increase in hypothalamic glutamatergic activity, whereas, HPD consumption under similar condition potentiated the age-related immunosuppression and increase in hypothalamic glutamatergic activity. These results suggest that (a) the age-associated immunosuppression may be inversely related to the hypothalamic glutamatergic activity and (b) consumption of diets having variable quantity of protein without variation of calorie content modulates immune response and hypothalamic glutamatergic activity depending upon age and duration of dietary supplementation.

Neuropsychological principia brevita: an application to traumatic (acquired) brain injury

The concepts and discoveries of modern neuroscience now challenge many of the presumptions that influence diagnostic decisions within neurology, psychiatry, and clinical neuropsychology. Many of these presumptions are derived from archaic bivariate models such as the mind-body argument, organic-functional dichotomy, and single lesion-single behaviour causality. Thirteen basic principles which may be useful for inferring more reliable and accurate relationships between microstructural function an clinical manifestations are developed.