title: Anesthesia increases in vivo N-([18F]fluoroethyl)piperidinyl benzilate binding to the muscarinic cholinergic receptor.
abstract: The in vivo binding of N-[18F]fluoroethyl-piperidinyl benzilate ([18F]FEPB) to the muscarinic cholinergic receptor was measured in awake and anesthetized rats. Studies were done using an equilibrium infusion technique to provide estimates of specific binding as distribution volume ratios. Anesthesia with either isoflurane or sodium pentobarbital produced a significant (65-90%) increase of radiotracer binding in receptor-rich brain regions (striatum, cortex, hippocampus) relative to awake controls. Pretreatment of anesthetized animals with the acetylcholinesterase inhibitor phenserine produced no further increases in radioligand binding, in contrast to the large (>70%) increases previously observed in awake animals following drug treatment. These studies demonstrate that anesthesia can produce significant changes in baseline biochemical measures that can obscure even very large effects of pharmacological challenges.
authors.affiliation: Division of Nuclear Medicine, Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109-0552, USA. mkilbour@umich.edu
authors.forename: Michael R
authors.initials: MR
authors.lastname: Kilbourn
authors.forename: Bing
authors.initials: B
authors.lastname: Ma
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Butch
authors.forename: Carole
authors.initials: C
authors.lastname: Quesada
authors.forename: Phillip S
authors.initials: PS
authors.lastname: Sherman
mesh_terms: D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D000818:Animals; D001561:Benzilates / Q000493:pharmacokinetics*; D001921:Brain / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D007530:Isoflurane / Q000008:administration & dosage*; D008297:Male; D008657:Metabolic Clearance Rate / Q000187:drug effects; D010424:Pentobarbital / Q000008:administration & dosage*; D010880:Piperidines / Q000493:pharmacokinetics*; D011485:Protein Binding / Q000187:drug effects; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D014018:Tissue Distribution / Q000187:drug effects
chemical_list: D018685:Anesthetics, Inhalation; D001561:Benzilates; D005462:Fluorine Radioisotopes; D006993:Hypnotics and Sedatives; C416656:N-(2-fluoroethyl)-3-piperidyl benzilate; D010880:Piperidines; D019275:Radiopharmaceuticals; D007530:Isoflurane; D010424:Pentobarbital