title: [125I] 3-quinuclidinyl 4-iodobenzilate: a high affinity, high specific activity radioligand for the M1 and M2-acetylcholine receptors.
abstract: We have prepared a radioiodinated ligand which binds with high affinity to the muscarinic acetylcholine receptor (m-AChR). A derivative of 3-quinuclidinyl benzilate, [125I] labeled (R) 1-aza-bicyclo(2.2.2)oct-3-yl (R,S)-alpha-hydroxy-alpha-(4-[125I]iodophenyl)phenyl acetate (4- IQNB ) exhibits an affinity for the m-AChR from corpus striatum higher than that of (R) [3H] QNB. Additionally, [125I] 4- IQNB exhibits receptor selectivity for the M1 receptor since the affinity for the receptor from dog and rat heart is lower than that using dog or rat corpus striatum.
mesh_terms: D000818:Animals; D003342:Corpus Striatum / Q000378:metabolism; D004285:Dogs; D005260:Female; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes; D007700:Kinetics; D009206:Myocardium / Q000378:metabolism; D011812:Quinuclidines / Q000378:metabolism*; D011813:Quinuclidinyl Benzilate / Q000378:metabolism*; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011976:Receptors, Muscarinic / Q000378:metabolism*
chemical_list: D007457:Iodine Radioisotopes; D011812:Quinuclidines; D011976:Receptors, Muscarinic; D011813:Quinuclidinyl Benzilate