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Nicotinic acetylcholine receptor subunit mRNA expression in adult and developing rat medullary catecholamine neurons
Author(s) -
O'Leary Kathryn T.,
Loughlin Sandra E.,
Chen Yiling,
Leslie Frances M.
Publication year - 2008
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.21833
Subject(s) - biology , tyrosine hydroxylase , nicotinic acetylcholine receptor , in situ hybridization , dorsal motor nucleus , messenger rna , nicotinic agonist , acetylcholine receptor , protein subunit , endocrinology , medicine , receptor , microbiology and biotechnology , dopamine , vagus nerve , gene , biochemistry , stimulation
Nicotinic acetylcholine receptors (nAChRs) mediate numerous visceral functions via medullary catecholamine (CA) neurons found in the nucleus tractus solitarius (NTS), dorsal motor nucleus of the vagus (DMV), and ventrolateral medulla (VLM). However, the nAChR subtypes involved are not known. We have therefore characterized expression of nine nAChR subunit mRNAs in adult and developing rat medullary CA nuclei using combined isotopic/nonisotopic in situ hybridization. Tyrosine hydroxylase (TH) mRNA, the CA‐synthesizing enzyme, was used as a marker for CA neurons, because these nuclei consist of heterogeneous populations of cells. Subunit mRNA expression varied within and between nuclei, along the rostrocaudal axis, between cell types, and across development. All CA neurons expressed β2 mRNA, whereas α2 mRNA was completely absent. α6 And β3 mRNA expression were restricted mainly to the VLM. α4, α5, And α7 mRNA expression was significantly greater in the rostral than in the caudal VLM. α3 And β4 mRNAs were highly expressed in the dorsal region of the NTS, whereas dense α7 mRNA expression was restricted to the DMV and ventral NTS. The remaining subunit mRNAs were detected to some degree in both DMV and NTS. Except for α4 mRNA, which peaked prenatally, expression levels of subunit transcripts in the NTS and DMV were lower during development compared with adults. In the VLM, α3, α4, and α5 mRNAs expression peaked perinatally, whereas α6 and β3 levels increased with age. These variations in nAChR subunit mRNA expression suggest that different receptor subtypes may produce function‐specific regulation of medullary CA systems. J. Comp. Neurol. 510:655–672, 2008. © 2008 Wiley‐Liss, Inc.