Autoradiographic localization of [125I]charybdotoxin binding sites in rat brain.
Charybdotoxin, a 37 amino acid peptide isolated from scorpion venom, is a potent inhibitor of potassium channel function. [125I]charybdotoxin was originally believed to be a selective ligand for the Ca(2+)-sensitive channel in many tissues, but it appears to bind only to a voltage-sensitive potassium channel in brain. We found high densities of [125I]charybdotoxin binding in lateral olfactory tract, interpeduncular nucleus and a variety of mesencephalic nuclei. Moderate levels were found in the cerebral cortex, medial thalamus, hypothalamus and selected thalamic nuclei. These results indicate that [125I]charybdotoxin identifies a potassium channel or channels with a unique distribution in the brain.
Gehlert
D R
DR
Central Nervous System Research, Lilly Corporate Center, Indianapolis 46285.
Gackenheimer
S L
SL
Robertson
D W
DW
D000818:Animals; D001345:Autoradiography / Q000379:methods; D001665:Binding Sites; D018999:Charybdotoxin; D007457:Iodine Radioisotopes; D007700:Kinetics; D008297:Male; D009928:Organ Specificity; D015221:Potassium Channels / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012604:Scorpion Venoms / Q000378:metabolism*
D007457:Iodine Radioisotopes; D015221:Potassium Channels; D012604:Scorpion Venoms; D018999:Charybdotoxin