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Cellular localization of corticotropin releasing factor mRNA in the ovine brain
S G Matthews1, R P Heavens, D J Sirinathsinghji
1Department of Behavioural Physiology, AFRC Institute of Animal Physiology and Genetics Research, Babraham, Cambridge, U.K.
Abstract:
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.
Insights
This study mapped corticotropin releasing factor (CRF) mRNA in sheep brains, finding it concentrated in the hypothalamus and brain stem. These findings suggest broader roles for CRF beyond stress response, influencing cognition and motor tasks.
Area of Science:
- Neuroscience
- Molecular Biology
- Endocrinology
Background:
- Corticotropin releasing factor (CRF) is a key regulator of the stress response.
- Understanding CRF mRNA distribution is crucial for elucidating its diverse physiological roles.
Purpose of the Study:
- To determine the regional and cellular distribution of CRF mRNA in the adult sheep brain.
- To investigate potential extrahypophysiotropic functions of CRF.
Main Methods:
- In situ hybridization histochemistry was employed to detect CRF mRNA.
- Quantitative analysis of labelled cell bodies was performed across various brain regions.
Main Results:
- Highest densities of CRF mRNA were observed in the paraventricular nucleus (PVN) of the hypothalamus and inferior olivary nuclei.
- CRF mRNA was also detected in cortical fields, locus coeruleus, parabrachial nucleus, and nucleus of the solitary tract.
- No CRF mRNA expression was found in the supraoptic nucleus or other specific diencephalic, telencephalic, and mesencephalic nuclei.
Conclusions:
- The dense CRF mRNA population in the PVN supports its role in regulating ACTH and cortisol secretion.
- Widespread CRF mRNA distribution suggests extrahypophysiotropic roles in integrating endocrine, autonomic, and behavioral responses to stress.
- CRF neurons may also be involved in controlling cognitive and motor tasks.