Cellular localization of corticotropin releasing factor mRNA in the ovine brain.

In this study in situ hybridization histochemistry was used to determine the regional distribution and cellular localization of corticotropin releasing factor (CRF) mRNA in the sheep brain. The highest densities of labelled cell bodies were found in the paraventricular nucleus (PVN) of the hypothalamus and in the inferior olivary nuclei in the brain stem. Labelled cells were also found in every major cortical field as well as in the vicinity of the locus coeruleus and parabrachial nucleus and nucleus of the solitary tract. No CRF mRNA-expressing cells were found in the supraoptic nucleus or other diencephalic nuclei or in telencephalic and mesencephalic nuclei. The dense population of CRF mRNA-expressing cells in the PVN support the major role of CRF in the modulation of adrenocorticotropin (ACTH) and cortisol secretion. Moreover, the widespread distribution of CRF mRNA transcripts would suggest that there are distinct populations of CRF neurons with extrahypophysiotropic roles involved in the coordination and integration of endocrine, autonomic and behavioural responses in response to stress as well as in the control of complex cognitive and motor tasks.