TY - JOUR T1 - The Use of a Cholinergic Fluorescent Probe for the Study of the Receptor Proteolipid JF - Molecular Pharmacology JO - Mol Pharmacol SP - 530 LP - 537 VL - 7 IS - 5 AU - G. WEBER AU - D. P. BORRIS AU - E. DE ROBERTIS AU - F. J. BARRANTES AU - J. L. LA TORRE AU - MARÍA C. LLORENTE DE CARLIN Y1 - 1971/09/01 UR - http://molpharm.aspetjournals.org/content/7/5/530.abstract N2 - A trimethylammonium derivative, 1-dimethylaminonaphthalene-5-sulfonamidoethyl-trimethylammonium perchlorate, was synthesized and used as a fluorescent probe for the study of the receptor proteolipid extracted from the electric organ of Electrophorus electricus. A special technique based on the preferred partition coefficient of the proteolipid for organic solvents and of the trimethylammonium derivative for water was developed. Such a method permits time accurate and rapid titration of the proteolipid with the cholinergic fluorescent probe and also the study of the action of other drugs competing for the binding sites. A cooperative type of interaction between the fluorescent trimethylammonium derivative and the receptor proteolipid was observed, and the competition of acetylcholine, dimethyl-d-tubocurarine, and decamethonium for the binding sites of the fluorescent probe was demonstrated. ACKNOWLEDGMENT The authors are indebted to Dr. Telma Caputi for her collaboration in the computation of the data. ER -