Localization of interleukin 6 mRNA and interleukin 6 receptor mRNA in rat brain

The cytokine interleukin 6 (IL6) has several effects on the central nervous system in addition to the well established regulation of the acute phase inflammatory response. Therefore, the distribution of IL6- and IL6 receptor mRNA in the rat brain has been investigated by in situ hybridization using [35S]-labeled oligonucleotides. The messages of both genes were found in the CA1-CA4 regions as well as in the dentate gyrus of the hippocampus, in the habenulae, the dorsomedial and the ventromedial hypothalamus, in the internal capsule, the optic tract and in the piriform cortex. These data indicate both neuronal and glial localization of IL6 and IL6 receptor and their involvement in an autocrine or paracrine action of the cytokine in centrally regulated functions including neuroendocrine control.