Characterization of l‐[3H]Nicotine Binding in Human Cerebral Cortex: Comparison Between Alzheimer's Disease and the Normal

Donna D. Flynn, Deborah C. Mash

Research output: Contribution to journalArticle

203 Scopus citations

Abstract

Putative nicotine receptors in the human cerebral cortex were characterized with L-[3H]nicotine. L-[3H]Nicotine binding was enhanced by the addition of Ca2+ and abolished in the presence of Na3EDTA. Association and dissociation of the ligand were rapid at 25°C with T( 1/2 ) values of 2 and 3 min, respectively. Saturation binding analysis revealed an apparent single class of sites with a dissociation constant of 5.6 nM and a Hill coefficient of 1.05. There was no effect of postmortem interval on the density of binding sites assayed up to 24 h in rat frontoparietal cortex. Nicotine binding in human cortical samples was also unaltered by increasing sampling delay. In human cortical membranes, binding site density decreased with normal aging. Receptor affinity and concentration in samples of frontal cortex (Brodmann area 10) from patients with Alzheimer's disease were comparable to age-matched control values. Samples of infratemporal cortex (Brodmann area 38) from patients with Alzhemier's disease had a 50% reduction in the number of L-[3H]nicotine sites. Choline acetyltransferase activity was significantly decreased in both cortical areas. Enzyme activities in the temporal pole were reduced to 20% of control values. These data indicate that postsynpatic nicotine receptors are spared in the frontal cortex in Alzheimer's disease. In the infratemporal cortex, significant numbers of receptors remain despite the severe reduction in choline acetyltransferase activity. Replacement therapy directed at these sites may be warranted in Alzheimer's disease.

Original languageEnglish (US)
Pages (from-to)1948-1954
Number of pages7
JournalJournal of neurochemistry
Volume47
Issue number6
DOIs
StatePublished - Dec 1986

Keywords

  • Alzheimer's disease
  • Human cerebral cortex
  • Nicotine
  • Receptor

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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