The KROX-24 protein, a new transcription regulating factor: expression in the rat central nervous system following afferent somatosensory stimulation.

The expression of the protein product encoded by the Krox-24 gene was investigated immunocytochemically in the central nervous system of adult rats. Immunoreactivity (IR) of the KROX-24 protein which is a nuclear transacting transcription factor, showed a pattern of nuclear staining. Basal KROX-24-IR was visible in the superficial layers of spinal dorsal horn and trigeminal nucleus, and in many areas of the brain including the cerebellum, nucleus raphe magnus, colliculi, periaqueductal gray, hypothalamus, geniculate nuclei, caudate putamen, amygdala, hippocampus, lateral septal nucleus, olfactory tubercle and cerebral cortex. Electrical stimulation of sciatic nerve A- and C-fibers, but not of A alpha- and A beta-fibers alone, induced transient expression of KROX-24 in numerous spinal neurons in the termination area of the stimulated nerve. One hour following the onset of this stimulation of the sciatic nerve the distribution of KROX-24-IR was investigated in the brain and compared to untreated rats. In stimulated animals, the KROX-24-IR was induced in many areas including the lateral reticular nucleus, parabrachial nucleus, periaqueductal gray, hypothalamus, amygdala and lateral habenular nucleus.