Expression of immediate early genes in sensory ganglia

C-Jun and c-Fos belong to the family of immediate early genes. Apart from t heir role as transcription factors, a basal expression was shown for them i n central nervous system tissues. The expression of c-Jun and c-Fos in sens ory ganglia of guinea pig, rat and murine sensory ganglia was examined unde r normal, unstimulated conditions by quantitative double-immunohistochemist ry. 4.6 +/- 2.8% of neuron-specific protein gene-product 9.5 -positive cell s in nodose ganglia, 51.6 +/- 2.1% in jugular ganglia, 46.4 +/- 3.0% in tri geminal ganglia and 42.5 +/- 1.3% of cervical dorsal root ganglia neurons w ere positive for c-Jun in the guinea pig (less than 1% for c-Fos). In rat a nd mouse, less than 1% of the sensory neurons exhibited c-Jun and c-Fos-imm unoreactivity. The high basal expression of c-Jun in guinea pig sensory neu rons suggests that in this species the presence of c-Jun does not only depe nd on specific stimulation and is not exclusively associated with neuronal plasticity of gene expression and functional changes.