Effects of age and visual experience on [3H] MK801 binding to NMDA receptors in the kitten visual cortex.

We have investigated the postnatal development of N-methyl-D-aspartate (NMDA) receptors in kitten neocortex by measuring the density of [3H] MK801 binding sites. NMDA receptor density in area 17 markedly increases between postnatal day 7 and 35, and then remains at a high level into adulthood. Similar temporal changes were observed in area 6. A brief period of binocular deprivation did not alter the density of [3H] MK801 binding sites in either brain region. However, dark rearing kittens from birth resulted in a significant decrease after 35 and 120 days in both area 17 and area 6. These results demonstrate that the density of NMDA receptors does not effectively predict the capacity for visual cortical plasticity in kitten neocortex. In addition, these results show that dark rearing produces significant effects in areas of the kitten neocortex not normally associated with visual function.