Comparison of the regional expression of nicotinic acetylcholine receptor α7 mRNA and [125I]‐α‐bungarotoxin binding in human postmortem brain

CR Breese, C Adams, J Logel… - Journal of …, 1997 - Wiley Online Library
CR Breese, C Adams, J Logel, C Drebing, Y Rollins, M Barnhart, B Sullivan, BK DeMasters…
Journal of Comparative Neurology, 1997Wiley Online Library
Neuronal nicotinic acetylcholine receptors are expressed in the human central nervous
system. A specific subtype of this receptor family, the α7 nicotinic acetylcholine receptor, is
thought to be the principal α‐bungarotoxin (αBTX)‐binding protein in mammalian brain.
Although the expression of this receptor subtype has been characterized in rat, no study has
specifically compared the expression of both the α7 gene and the localization of BTX
binding sites in human brain. Expression of α7 mRNA and receptor protein in human …
Abstract
Neuronal nicotinic acetylcholine receptors are expressed in the human central nervous system. A specific subtype of this receptor family, the α7 nicotinic acetylcholine receptor, is thought to be the principal α‐bungarotoxin (αBTX)‐binding protein in mammalian brain. Although the expression of this receptor subtype has been characterized in rat, no study has specifically compared the expression of both the α7 gene and the localization of BTX binding sites in human brain. Expression of α7 mRNA and receptor protein in human postmortem brain tissue was examined by in situ hybridization and [125I]‐α‐bungarotoxin autoradiography, respectively, with particular emphasis on regions associated with sensory processing. Regions with high levels of both α7 gene expression and [125I]‐αBTX binding include the nucleus reticularis of the thalamus, the lateral and medial geniculate bodies, the basilar pontine nucleus, the horizontal limb of the diagonal band of Broca, the nucleus basalis of Meynert, and the inferior olivary nucleus. High‐to‐moderate levels of α7 probe hybridization were also seen in the hippocampus and the cerebral cortex; however, there was a reduced or variable degree of [125I]‐αBTX binding in these regions compared with the level of probe hybridization. In most brain regions, [125I]‐αBTX binding was localized to neuronal cell bodies similar in morphology to those that exhibited α7 hybridization, suggesting that the high‐affinity [125I]‐αBTX binding sites in the human brain are likely to be principally composed of α7 receptor subtypes. J. Comp. Neurol. 387:385–398, 1997. © 1997 Wiley‐Liss, Inc.
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