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Molecular and cellular characterization of nicotinic acetylcholine receptor subtypes in the arcuate nucleus of the mouse hypothalamus
Author(s) -
Calarco Cali A.,
Li Zhiying,
Taylor Seth R.,
Lee Somin,
Zhou Wenliang,
Friedman Jeffrey M.,
Mineur Yann S.,
Gotti Cecilia,
Picciotto Marina R.
Publication year - 2018
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.13966
Subject(s) - arcuate nucleus , nicotinic agonist , arc (geometry) , cytisine , nicotinic acetylcholine receptor , chemistry , protein subunit , hypothalamus , nicotine , medicine , endocrinology , agonist , microbiology and biotechnology , receptor , biology , biochemistry , geometry , mathematics , gene
Nicotine, acting through nicotinic acetylcholine receptors ( nAChR s), increases the firing rate of both orexigenic agouti‐related peptide (Ag RP ) and anorexigenic pro‐opiomelanocortin ( POMC ) neurons in the arcuate nucleus of the hypothalamus ( ARC ), yet nicotine and other nAChR agonists decrease food intake in mice. Viral‐mediated knockdown of the β4 nAChR subunit in all neuronal cell types in the ARC prevents the nicotinic agonist cytisine from decreasing food intake, but it is not known whether the β4 subunit is selectively expressed in anorexigenic neurons or how other nAChR subtypes are distributed in this nucleus. Using translating ribosome affinity purification ( TRAP ) on ARC tissue from mice with ribosomes tagged in either Ag RP or POMC cells, we examined nAChR subunit mRNA levels using real‐time PCR . Both Ag RP and POMC cells express a comparable panel of nAChR subunits with differences in α7 mRNA levels and a trend for difference in α4 levels, but no differences in β4 expression. Immunoprecipitation of assembled nAChR s revealed that the β4 subunit forms assembled channels with α3, β2 and α4, but not other subunits found in the ARC . Finally, using cell type‐selective, virally delivered small hairpin RNA s targeting either the β4 or α7 subunit, we examined the contribution of each subunit in either Ag RP or POMC cells to the behavioural response to nicotine, refining the understanding of nicotinic regulation of this feeding circuit. These experiments identify a more complex set of nAChR s expressed in ARC than in other hypothalamic regions. Thus, the ARC appears to be a particular target of nicotinic modulation.