The aim of this study was to investigate the expression of serine/threonine kinase receptors in the brain following traumatic brain injury. We report here that, the recently cloned and characterized bone morphogenetic protein (BMP) receptor type II (BMPR-II) and the activin receptor type IA (ActR-1) Act: mRNAs were simultaneously up-regulated in neurones in the dentate gyrus 6 h after a mild cerebral contusion injury. This findings was specific for these receptors since other investigated genes (i.e. ActR-II, ActR-IB, trkB and c-fos) showed other temporal patterns. These data suggest that type I and type II receptors act together in signal transduction in vivo and that BMPs may be involved in neuronal plasticity after traumatic brain injury.