Localization of [3H]nicotine, [3H]cytisine, [3H]epibatidine, and [125I]alpha-bungarotoxin binding sites in the brain of Macaca mulatta.
We determined the localization of [(3)H]nicotine, [(3)H]cytisine, [(3)H]epibatidine, and [(125)I]alpha-bungarotoxin binding sites in the brain of rhesus monkey by means of receptor autoradiography. The labelings by [(3)H]nicotine, [(3)H]cytisine, and [(3)H]epibatidine were highly concordant, except for epibatidine. Layer IV of some cortical areas, most thalamic nuclei, and presubiculum displayed high levels of labeling for the three ligands. Moderate levels of binding were detected in the subiculum, the septum, and the mesencephalon. Low levels were present in layers I-II and VI of the cortex, the cornu Ammonis, the dentate gyrus, and the amygdala. In addition, the level of epibatidine labeling was very high in the epithalamic nuclei and the interpeduncular nucleus, whereas labeling by nicotine and cytisine was very weak in the same regions. The distribution of [(125)I]alpha-bungarotoxin binding differed from the binding of the three agonists. The labeling was dense in layer I of most cortical areas, dentate gyrus, stratum lacunosum-moleculare of CA1 field, several thalamic nuclei, and medial habenula. A moderate labeling was found in layers V and VI of the prefrontal and frontal cortices, layer IV of primary visual cortex, amygdala, septum, hypothalamus, and some mesencenphalic nuclei. A weak signal was also detected in subiculum, claustrum, stratum oriens, and stratum lucidum of cornu Ammonis and also in some mesencephalic nuclei. The distribution of nicotine, cytisine, and epibatidine bindings corresponds broadly to the patterns observed in rodents, with the marked exception of the epithalamus. However, in monkey, those distributions match the distribution of alpha2 messenger RNA, rather than that of alpha4 transcripts as it exists in rodent brains. The distribution of the binding sites for alpha-bungarotoxin is larger in the brain of rhesus monkeys than in rodent brain, suggesting a more important role of alpha7 receptors in primates.
CNRS URA 2182-Récepteurs et Cognition, Institut Pasteur, 75724 Paris Cedex 15, France.
Zhi-Yan
ZY
Han
Michele
M
Zoli
Ana
A
Cardona
Jean-Pierre
JP
Bourgeois
Jean-Pierre
JP
Changeux
Nicolas
N
Le Novère
D000470:Alkaloids / Q000378:metabolism; D000818:Animals; D001345:Autoradiography; D001392:Azocines; D001665:Binding Sites; D001921:Brain / Q000378:metabolism*; D001931:Brain Mapping / Q000379:methods*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000378:metabolism; D004027:Diencephalon / Q000378:metabolism; D008253:Macaca mulatta; D008297:Male; D008636:Mesencephalon / Q000378:metabolism; D009538:Nicotine / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D018722:Nicotinic Agonists / Q000378:metabolism; D011725:Pyridines / Q000378:metabolism; D011807:Quinolizines; D011869:Radioligand Assay; D011978:Receptors, Nicotinic / Q000378:metabolism*; D013687:Telencephalon / Q000378:metabolism; D014018:Tissue Distribution; D064569:alpha7 Nicotinic Acetylcholine Receptor; D000093843:Quinolizidine Alkaloids
D000470:Alkaloids; D001392:Azocines; D019086:Bridged Bicyclo Compounds, Heterocyclic; D009538:Nicotine; D018722:Nicotinic Agonists; D011725:Pyridines; D011807:Quinolizines; D011978:Receptors, Nicotinic; D064569:alpha7 Nicotinic Acetylcholine Receptor; C004712:cytisine; D000093843:Quinolizidine Alkaloids; C082748:epibatidine