Autoradiographic localization of alpha-bungarotoxin-binding sites in the carotid body of the rat.
Radioiodinated alpha-bungarotoxin (alpha-Bgt) was used to localize alpha-Bgt-acetylcholine receptors in the carotid body of the rat. The gamma spectrometer analyses indicated a high uptake of [125I] alpha-Bgt in carotid bodies incubated in vitro (1.51 fmole per organ). Incorporation of the isotope was effectively blocked by pretreatment of carotid bodies with d-tubocurarine and unlabeled alpha-Bgt, but not by atropine. Light microscopic autoradiography showed a heavy labeling of some parenchymal cells. Electron-microscopic autoradiography revealed that labeling was localized along the interface between parenchymal cells, especially where their cytoplasmic processes engage in complex interdigitations. The silver grain counts on electron-microscopic autoradiographs suggest that labelings are preferentially associated with the plasma membrane of certain Type I cells. It is suggested that these Type I cells in the rat's carotid body probably are provided with nicotinic acetylcholine receptors on their plasma membranes.
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001345:Autoradiography; D002038:Bungarotoxins / Q000378:metabolism; D002344:Carotid Body / Q000032:analysis* / Q000648:ultrastructure; D002462:Cell Membrane / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D011950:Receptors, Cholinergic / Q000032:analysis*; D011978:Receptors, Nicotinic; D014403:Tubocurarine / Q000494:pharmacology; D064569:alpha7 Nicotinic Acetylcholine Receptor
D002038:Bungarotoxins; C579165:Chrna7 protein, rat; D011950:Receptors, Cholinergic; D011978:Receptors, Nicotinic; D064569:alpha7 Nicotinic Acetylcholine Receptor; D001285:Atropine; D014403:Tubocurarine