GABA(B) BINDING-SITES IN EARLY ADULT AND AGING RAT-BRAIN

The effect of aging on GABA(B) binding was investigated in rat brain. Receptor autoradiography was used to investigate both GABA(B) and GABA(A) binding at 2 months, 3 months, 13 months, and 23 months. GABA(B) binding decreases significantly between 2 months and 23 months of age, as does GABA(A) binding, with was investigated in rat brain. Receptor autoradiography was used to investigate both GABA(B) and GABA(A) binding at 2 months, 3 months, 13 months, and 23 months. GABA(B) binding decreases significantly between 2 months and 23 months of age, as does GABA(A) binding, with the greatest decrease between 2 and 3 months. The decrease in GABA(B) binding appears to be due to a decrease in binding site affinity rather than a decrease in receptor density. The noncompetitive GABA(B) antagonist zinc, the competitive GABA(B) antagonist CGP 35348, and the guanyl nucleotide analogue GTP-gamma-S all inhibit GABA(B) binding identically in 2 month and 23 month brain. These data indicate subtle age-related changes in the GABA(B) binding in early adult life but little change with senescence.