Journals of Gerontology Series A: Biological Sciences and Medical Sciences, Vol 51, Issue 2 B141-B147, Copyright © 1996 by The Gerontological Society of America
Glycine enhances binding to the NMDA receptor complex in aged mice, but does not correct the aging change
KR Magnusson
Department of Anatomy and Neurobiology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523, USA.
The purpose of this study was to determine whether glycine is effective in
correcting the age-related change in the N-methyl-D-aspartate (NMDA)
receptor complex. Autoradiographic analysis of [3H]MK801 and NMDA-
displaceable [3H]glutamate binding was performed with 0, 10, 30 and 100
microM glycine on brain tissue from 3-, 10-, and 24-30-month-old C57B1
mice. Glycine, even at 10 microM, enhanced binding to both the NMDA and
MK801 binding sites in all age groups. Glycine was not able to reduce the
absolute difference in [3H]glutamate binding to NMDA sites between 3- and
24-month-olds. Low micromolar concentrations of glycine exacerbated the
aging difference in [3H]MK801 binding between young and old mice, but 100
microM glycine produced smaller aging differences that were similar to
those seen with no glycine. This study suggests that glycine may enhance
NMDA receptor function in old animals, but it does not appear to correct
the underlying problem with the NMDA receptor in aged animals.
