title: Synthesis and in vivo characterization of D-(+)-(N1-[11C]methyl)-2-Br-LSD: a radioligand for positron emission tomographic studies of serotonin 5-HT2 receptors.
abstract: D-(+)-N1-Methyl-2-Br-LSD (MBL), which displays high affinity and selectivity for serotonin receptors in vitro, has been labeled with carbon-11 for localization of cerebral serotonin 5-HT2 receptors by positron emission tomography. [11C]MBL was prepared from [11C]iodomethane and D-(+)-2-Br-LSD within 20 min from end of bombardment. The average specific activity of [11C]MBL was 2300 mCi/mumol and the average radiochemical yield was 17%, both at end of synthesis. The in vivo regional distribution of radioactivity in brain after i.v. administration of [11C]MBL to mice paralleled the known density of serotonin 5-HT2 receptors. The maximum specific binding, defined by a frontal cortex to cerebellum radioactivity concentration ratio of 5.4 to 1, was reached 30 min postinjection. Administration of ketanserin, a potent serotonin 5-HT2 receptor antagonist, markedly blocked radioligand binding in all brain regions examined except cerebellum.
authors.affiliation: Department of Environmental Health Sciences, Johns Hopkins Medical Institutions, Baltimore, MD 21205.
authors.forename: J R
authors.initials: JR
authors.lastname: Lever
authors.forename: R F
authors.initials: RF
authors.lastname: Dannals
authors.forename: A A
authors.initials: AA
authors.lastname: Wilson
authors.forename: H T
authors.initials: HT
authors.lastname: Ravert
authors.forename: U
authors.initials: U
authors.lastname: Scheffel
authors.forename: B J
authors.initials: BJ
authors.lastname: Hoffman
authors.forename: P R
authors.initials: PR
authors.lastname: Hartig
authors.forename: D F
authors.initials: DF
authors.lastname: Wong
authors.forename: H N
authors.initials: HN
authors.lastname: Wagner
mesh_terms: D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging*; D002250:Carbon Radioisotopes; D007553:Isotope Labeling / Q000379:methods*; D008238:Lysergic Acid Diethylamide / Q000031:analogs & derivatives*; D008297:Male; D051379:Mice; D011985:Receptors, Serotonin / Q000378:metabolism*; D014055:Tomography, Emission-Computed
chemical_list: D002250:Carbon Radioisotopes; D011985:Receptors, Serotonin; C058328:N(1)-methyl-2-bromo-lysergic acid diethylamide; D008238:Lysergic Acid Diethylamide