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Nucleus incertus corticotrophin-releasing factor 1 receptor signalling regulates alcohol seeking in rats

journal contribution
posted on 2017-11-01, 00:00 authored by L C Walker, H E Kastman, J A Koeleman, Craig SmithCraig Smith, C J Perry, E V Krstew, A L Gundlach, A J Lawrence
Alcoholism is a chronic relapsing disorder, and stress is a key precipitant of relapse. The nucleus incertus (NI) is highly responsive to corticotrophin-releasing factor (CRF) and psychological stressors, receives a CRF innervation and expresses CRF1 and CRF2 receptor mRNA. Furthermore, the ascending NI relaxin-3 system is implicated in alcohol seeking in rats. Therefore, in alcohol-preferring rats, we examined the effect of bilateral injections into the NI of the CRF1 receptor antagonist, CP376395 or the CRF2 receptor antagonist, astressin-2B on yohimbine-induced reinstatement of alcohol seeking. Using quantitative PCR analysis of NI micropunches, we assessed the effects of chronic alcohol consumption on gene expression profiles for components of the relaxin-3 and CRF systems. Bilateral intra-NI injections of CP376395 (500 ng/0.25 µl) attenuated yohimbine-induced reinstatement of alcohol seeking. In contrast, intra-NI injections of astressin-2B (200 ng/0.25 µl) had no significant effect. In line with these data, CRF1 , but not CRF2 , receptor mRNA was upregulated in the NI following chronic ethanol intake. Relaxin family peptide 3 receptor mRNA was also increased in the NI following chronic ethanol. Our quantitative PCR analysis also identified CRF mRNA within the rat NI, and the existence of a newly identified population of CRF-containing neurons was subsequently confirmed by detection of CRF immunoreactivity in rat and mouse NI. These data suggest that NI neurons contribute to reinstatement of alcohol seeking, via an involvement of CRF1 signalling. Furthermore, chronic ethanol intake leads to neuroadaptive changes in CRF and relaxin-3 systems within rat NI.

History

Journal

Addiction biology

Volume

22

Issue

6

Pagination

1641 - 1654

Publisher

Wiley

Location

Hoboken, N.J.

eISSN

1369-1600

Language

eng

Publication classification

C Journal article; C1 Refereed article in a scholarly journal

Copyright notice

2016, Society for the Study of Addiction