Somatosensory regulation of serotonin release in the central nucleus of the amygdala is mediated via corticotropin releasing factor and gamma-aminobutyric acid in the dorsal raphe nucleus
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Noxious cutaneous stimulation increases, whereas innocuous cutaneous stimulation decreases serotonin (5-HT) release in the central nucleus of the amygdala (CeA) in anesthetized rats. In the present study, we investigated the contribution of corticotropin releasing factor (CRF) receptors and gamma-aminobutyric acid (GABA) receptors in the dorsal raphe nucleus (DRN) to those responses. Release of 5-HT in the CeA was monitored by microdialysis before and after 10-min stimulation by pinching or stroking. Increased 5-HT release in the CeA in response to pinching was abolished by CRF2 receptor antagonism in the DRN. Decreased 5-HT release in the CeA in response to stroking was abolished by either CRF1 receptor antagonism or GABAA receptor antagonism in the DRN. These results suggest that opposite responses of 5-HT release in the CeA to noxious versus innocuous stimulation of the skin are due to separate contributions of CRF2, CRF1 and GABAA receptors in the DRN.
KeywordsCRF1 receptor CRF2 receptor GABAA receptor Microdialysis Pinching Stroking
We thank Mr. Yuki Masuya, Eicom Co., Ltd., for his skillful technical assistance in measuring 5-HT. We also thank Mr. Noriaki Takagi for his partial contribution to this study. The present study was supported by the JSPS KAKENHI Grant (no. 16K01465) to M.K.
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Conflict of interest
The authors declare that they have no conflict of interest.
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