[3H]D-aspartic acid release in brain slices of adult and aged Fischer 344 rates.

Alterations in glutamate content and uptake have been reported to occur in aged animals. The present studies used [3H]D-Aspartic acid [( 3H]-D-ASP) release as a marker for glutamate neurotransmission. Frequency dependent [3H]-D-ASP release was measured in adult (8 month) and aged (28-30 month) Fischer 344 rats. Relatively high stimulation frequencies (greater than 10 Hz) were required to induce [3H]-D-ASP release in both adult and aged F344 rats in temporal cortex and hippocampus. In both brain areas aged animals showed significantly more [3H]-D-ASP release than adult animals. Kainic acid 1 mM failed to induce the release of [3H]-D-ASP in either temporal cortex or hippocampus. Omega conotoxin GVIA (5 x 10(-9) M) a N and L type voltage sensitive calcium channel antagonist failed to inhibit [3H]-D-ASP stimulated release. These results demonstrate an increase in [3H]-D-ASP release in aged compared to adult F344 rats. The data also suggest a novel calcium channel may be involved in [3H]-D-ASP release.