CREB-1 AND CREB-2 IMMUNOREACTIVITY IN THE RAT-BRAIN

This study is focused to learn about the cellular localization of tran scription factors binding to the cAMP response element-CREBs-in the br ain of normal rats and in animals subjected to excitotoxic cell damage . For this purpose, CREB-1 and CREB-2 immunoreactivity is examined in the developing and adult rat brain under physiological conditions, and following systemic kainic acid (KA) injection at convulsant doses in the adult, as a validated experimental model of excitotoxic injury. CR EB-1 immunoreactivity is constitutively expressed in periventricular g lia and Bergmann glia, and appears in reactive astrocytes following KA -induced excitotoxic cell damage. In contrast, CREB-2 is constitutivel y expressed in all neurons of the cerebrum, cerebellum and brain stem in the developing and adult brain. CREB-2 immunoreactivity is not incr eased following KA excitotoxic cell damage. These results demonstrate that CREB-1 and CREB-2 in the brain of the rat are localized in separa te cellular compartments and that their expression is differentially r egulated in pathologic states.