Aging of membrane transport mechanisms in the central nervous system—2-deoxy-D-glucose transport in cortical synaptosomes from the long-evans rat

Abstract Initial velocity of uptake of 2-deoxy- D -glucose (2- D g) has been measured in cortical synaptosomes from 30-month-old rats and compared to results from 2-month-old animals. No significant changes were found in velocity of uptake at any [Na] and [2- D g] used. The velocity data were fitted to the rate equation by the use of computer optimization techniques, and the kinetic constants were estimated. The predicted diffusion constants are so low that no measurable diffusive uptake is predicted for either 2- or 30-month animals. The kinetic constants V m (maximal rate of uptake) and K t (Michaelis-Menten constant) were found not to change with age. The results contrast to a similar previous study of glutamate transport, in which substantial declines in carrier capability were found in the 30-month age group.