We previously showed that the expression of troponin T1 (Tnnt 1) was induced in the central nervous system (CNS) of adultmice 30 min after treatment with ketamine, a glutamate N-methyl-D-aspartic acid (NMDA) receptor antagonist. We hypothesized that Tnnt 1 expression may be an early molecular biomarker of stress response in the CNS of mice. To further evaluate this hypothesis, we investigated the regional expression of Tnnt 1 in the mouse brain using RNA in situ hybridization 4 h after systemic exposure to interferon-a (IFN-a) and gamma ionizing radiation, both of which have be associated with wide ranges of neuropsychiatric complications. Adult B6C3F1 male mice were treated with either human IFN-a (a single i.p. injection at 1 x 105 IU/kg) or whole body gamma-radiation (10 cGy or 2 Gy). Patterns of Tnnt 1 transcript expression were compared in various CNS regions after IFN-a, radiation and ketamine treatments (previous study). Tnnt 1 expression was consistently induced in pyramidal neurons of cerebral cortex and hippocampus after all treatment regimens including 10 cGy of ionizing radiation. Regional expression of Tnnt 1 was induced in Purkinje cells of cerebellum after ionizing radiation and ketamine treatment; but not after IFN-a treatment. None of the three treatments induced Tnnt 1 expression in glial cells. The patterns of Tnnt 1 expression in pyramidal neurons of cerebral cortex and
hippocampus, which are both known to play important roles in cognitive function, memory and emotion, suggest that the expression of Tnnt 1 may be an early molecular biomarker of induced CNS stress.