Focal brain injury increases activin beta A mRNA expression in hippocampal neurons

The role of activin in the mammalian brain is of increasing interest as evidence accumulates to suggest a number of different neural functions. Here, we report that activin beta A mRNA is transiently induced in dentate gyrus neurons after unilateral mechanical brain injury by saline injection. Expression is dependent on NMDA receptor activation since pretreatment with MK801 (5 mg/kg, i.p.) largely attenuates the signal. Induction also requires de novo protein synthesis, as cycloheximide (10 mg/kg, i.p.) pretreatment abolishes the expression of activin beta A mRNA 1h after injury. These results show that activin beta A mRNA expression is regulated by excitatory activity induced by focal brain injury and suggests a possible neuroplastic role in the recovery from such injury.