To determine if age-related compensations in GAD67 mRNA expression occur during development, we assessed GAD67 mRNA levels in four week old CB1R−/− and WT mice. In these mice, cortical GAD67 mRNA levels did not differ (F1,12=0.2; p=0.671) between CB1R−/− (536.7 ± 41.4 nCi/g) and WT mice (549.4 ± 64.7 nCi/g).