Alpha-7 nicotinic receptor expression by two distinct cell types in the dorsal raphe nucleus and locus coeruleus of rat

Alpha-7 nicotinic receptor expression by two distinct cell types in the dorsal raphe nucleus and... The α7 nicotinic acetylcholine receptor (nAChR) subunit can be assembled to form a homomeric-pentamer with high permeability to calcium. Although the expression of the α7-nAChR has been demonstrated throughout the CNS, the neurochemical phenotype of neurons expressing α7 remains to a large extent unknown. Using an antibody against the α7 nAChR subunit, immunohistochemical staining was observed in rat dorsal raphe nucleus (DRN) and locus coeruleus (LC), serotonergic and noradrenergic brainstem nuclei, respectively. In both the DRN and LC, there appeared to be two histologically distinct α7-expressing cell types as distinguished by size, i.e. large versus small diameter. In rats treated with either a serotonergic (5,7-dihydroxytryptamine) or noradrenergic (anti-dopamine-β-hydroxylase saporin) neurotoxin, tryptophan hydroxylase and tyrosine hydroxylase immunostaining was abolished, respectively. Similarly, the α7-positive large-diameter cells were no longer detectable, suggesting that these cells were serotonergic DRN and noradrenergic LC neurons. Indeed, double-labeling experiments revealed in the large cell types coexpression of α7 with tryptophan hydroxylase in the DRN and with tyrosine hydroxylase in the LC of saline-treated rats. In contrast to the large-diameter cells, the α7-positive small-diameter cells were neither serotonergic nor adrenergic, and were still detected in both the DRN and LC of lesioned rats. Moreover, cell counts revealed an increase number of these cells in lesioned rats with expression of α7 in somal processes not seen in non-lesioned controls. Double labeling revealed coexpression of α7 and GABA within the majority, but not all, of the toxin-resistant cells. The results of these studies suggest that both serotonergic and noradrenergic neurons express α7 nAChRs. In addition, there appears to be a small-diameter cell-type in both the DRN and LC, possibly a GABAergic interneuron, expressing α7 that may be regulated by neurotoxic injury. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Brain Research Elsevier

Alpha-7 nicotinic receptor expression by two distinct cell types in the dorsal raphe nucleus and locus coeruleus of rat

Brain Research, Volume 938 (1) – May 31, 2002

Loading next page...
 
/lp/elsevier/alpha-7-nicotinic-receptor-expression-by-two-distinct-cell-types-in-w1sGxiy00C
Publisher
Elsevier
Copyright
Copyright © 2002 Elsevier Science B.V.
ISSN
0006-8993
DOI
10.1016/S0006-8993(02)02485-X
Publisher site
See Article on Publisher Site

Abstract

The α7 nicotinic acetylcholine receptor (nAChR) subunit can be assembled to form a homomeric-pentamer with high permeability to calcium. Although the expression of the α7-nAChR has been demonstrated throughout the CNS, the neurochemical phenotype of neurons expressing α7 remains to a large extent unknown. Using an antibody against the α7 nAChR subunit, immunohistochemical staining was observed in rat dorsal raphe nucleus (DRN) and locus coeruleus (LC), serotonergic and noradrenergic brainstem nuclei, respectively. In both the DRN and LC, there appeared to be two histologically distinct α7-expressing cell types as distinguished by size, i.e. large versus small diameter. In rats treated with either a serotonergic (5,7-dihydroxytryptamine) or noradrenergic (anti-dopamine-β-hydroxylase saporin) neurotoxin, tryptophan hydroxylase and tyrosine hydroxylase immunostaining was abolished, respectively. Similarly, the α7-positive large-diameter cells were no longer detectable, suggesting that these cells were serotonergic DRN and noradrenergic LC neurons. Indeed, double-labeling experiments revealed in the large cell types coexpression of α7 with tryptophan hydroxylase in the DRN and with tyrosine hydroxylase in the LC of saline-treated rats. In contrast to the large-diameter cells, the α7-positive small-diameter cells were neither serotonergic nor adrenergic, and were still detected in both the DRN and LC of lesioned rats. Moreover, cell counts revealed an increase number of these cells in lesioned rats with expression of α7 in somal processes not seen in non-lesioned controls. Double labeling revealed coexpression of α7 and GABA within the majority, but not all, of the toxin-resistant cells. The results of these studies suggest that both serotonergic and noradrenergic neurons express α7 nAChRs. In addition, there appears to be a small-diameter cell-type in both the DRN and LC, possibly a GABAergic interneuron, expressing α7 that may be regulated by neurotoxic injury.

Journal

Brain ResearchElsevier

Published: May 31, 2002

References

  • Reduced nicotinic receptor-mediated antinociception following in vivo antisense knock-down in rat
    Bitner, R.S.; Nikkel, A.L.; Curzon, P.; Donnelly-Roberts, D.L.; Puttfarcken, P.S.; Namovic, M.; Jacobs, I.C.; Meyer, M.D.; Decker, M.W.
  • In vitro neuroprotective properties of the novel cholinergic channel activator (ChCA), ABT-418
    Donnelly-Roberts, D.L.; Xue, I.C.; Arneric, S.P.; Sullivan, J.P.
  • Genetic mapping of a major susceptibility locus for juvenile myoclonic epilepsy on chromosome 15q
    Elmslie, F.V.; Rees, M.; Williamson, M.P.; Kerr, M.; Kjeldsen, M.J.; Pang, K.A.; Sundqvist, A.; Friis, M.L.; Chadwick, D.; Richens, A.; Covanis, A.; Santos, M.; Arzimanoglou, A.; Panayiotopoulos, C.P.; Curtis, D.; Whitehouse, W.P.; Gardiner, R.M.
  • Serotonin 5-HT(2) receptors activate local GABA inhibitory inputs to serotonergic neurons of the dorsal raphe nucleus
    Liu, R.; Jolas, T.; Aghajanian, G.
  • Physiological diversity of nicotinic acetylcholine receptors expressed by vertebrate neurons
    McGehee, D.S.; Role, L.W.
  • Effects of nicotine and mecamylamine on rat dorsal raphe neurons
    Mihailescu, S.; Palomero-Rivero, M.; Meade-Huerta, P.; Maza-Flores, A.; Drucker-Colin, R.
  • The diversity of neuronal nicotinic acetylcholine receptors
    Sargent, P.

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create folders to
organize your research

Export folders, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off