RT Journal Article SR Electronic T1 Multiple Specific Binding Targets for Inhaled Anesthetics in the Mammalian Brain JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 172 OP 179 DO 10.1124/jpet.300.1.172 VO 300 IS 1 A1 Maryellen Fazen Eckenhoff A1 Kin Chan A1 Roderic G. Eckenhoff YR 2002 UL http://jpet.aspetjournals.org/content/300/1/172.abstract AB Previous work showed widespread saturable binding of halothane in rat brain. To determine whether this represents selective binding to a few widespread proteins or less selective binding to many different proteins, we used [14C]halothane photolabeling and quantitative electrophoresis/autoradiography in rat cerebellar homogenates. Many proteins incorporate label. Stoichiometry values ranged from 0 to 4 at 0.2 mM [14C]halothane in a group of 24 randomly selected protein bands. Apparent IC50 values from unlabeled halothane competition experiments ranged from 0.2 to 2.0 mM, with soluble protein having significantly lower values (higher affinity) than membrane protein. Chloroform inhibited halothane labeling similar to unlabeled halothane but with higher apparent IC50 values, whereas isoflurane and an anesthetic, cyclobutane (1-chloro-1,2,2-trifluorocyclobutane), inhibited halothane labeling to a smaller degree. A nonanesthetic, cyclobutane (1,2-dichlorohexafluorocyclobutane), inhibited halothane labeling the least. We conclude that halothane binding motifs are sufficiently degenerate to be found in many proteins, both soluble and membrane-bound. PBSphosphate-buffered salinePAGEpolyacrylamide gel electrophoresisRDreflective densitiesODoptical densitiesPDBProtein Data BankF31-chloro-1,2,2-trifluorocyclobutaneF61,2-dichlorohexafluorocyclobutane