AGE-DEPENDENT CHANGES IN BRAIN GABA TURNOVER RATES IN 2 INBRED STRAINS OF MICE

GABA steady-state levels and turnover rates were determined in 15 brain areas of 21 day- and 3-mo.-old DBA/2J (DBA) and C57B1/6J (C57) mice. These 2 inbred strains differ by their susceptibility to audiogenic seizures; the involvement of GABAergic neurotransmission was suggested in the control of this behavior. Turnover rates are generally higher at 21 days than at 3 mo. of age. There are few significant differences in the GABA steady-state levels between 21 day old seizure-prone DBA mice when compared with seizure-resistant C57 mice. In the DBA mice, the steady-state level is higher in the olfactory bulbs and lower in the posterior colliculus and the olfactory tubercles than in the C57 mice. Although there are some significant differences in GABA turnover rates and steady-state levels, intra or inter strains, it is difficult to correlate directly these differences with seizure susceptibility.