Measuring nicotinic receptors with characteristics of alpha4beta2, alpha3beta2 and alpha3beta4 subtypes in rat tissues by autoradiography.

摘要: Comparison of [125I]epibatidine and 5-[125I]iodo-3-(2-azetidinylmethoxy)pyridine ([125I]A-85380) autoradiography showed evidence for nicotinic receptor heterogeneity. To identify the subtypes, we performed in presence cytisine or A-85380. By comparing these results with binding data from human embryonic kidney (HEK) 293 cells stably transfected different combinations rat subunits, were able to quantify three distinct populations sites characteristics α4β2, α3β2 α3β4 receptors. Although predominant subtype brain was non-α4β2 prominent many regions. In habenulo-peduncular system, cerebellum, substantia gelatinosa, medullary nuclei, α3β4-like accounted more than 40% binding, nearly all superior cervical ganglion pineal gland. Other regions enriched included locus ceruleus, dorsal tegmentum, subiculum anteroventral thalamic nucleus. Regions α3β2-like visual system structures, certain geniculate dopaminergic The combination using a broad spectrum radioligand selectivecompetitors, defined subtypes expression systems, allowed us relative subtypes.