title: PET study of the [11C]raclopride binding in the striatum of the awake cat: effects of anaesthetics and role of cerebral blood flow.
abstract: Cats were trained to stay in a containment box, without developing any signs of behavioural stress, while their head was maintained in a position that allowed positron emission tomography (PET) experiments to be performed. The binding potential for [(11)C]raclopride (BP(raclo)), a radioligand with good specificity for dopamine (DA) receptors of the D(2) type, was measured in the striatum and in three experimental situations: awake, anaesthetised with ketamine (50 mg kg(-1) h(-1); i.m.) and anaesthetised with halothane (1.5%). Non-specific binding was evaluated in the cerebellum. In the striatum of both sides, the BP(raclo) was unmodified by ketamine anaesthesia when compared with awake animals. In contrast, a large increase in BP(raclo) was observed under halothane anaesthesia. The non-specific binding of [(11)C]raclopride, evaluated in the cerebellum, was also unchanged under ketamine anaesthesia but greatly increased under halothane anaesthesia. To evaluate whether changes in the cerebral blood flow (CBF) resulting from the different experimental situations could be at the root of these discrepancies, injections of [(15)O]H(2)O were performed; measurements revealed a drastically increased CBF under halothane anaesthesia and a slight enhancement under ketamine anaesthesia, when compared with the waking state. These results are the first to be obtained on this topic in awake cats, and show that the BP(raclo) is greatly dependent on alterations in the CBF.
authors.affiliation: CERMEP, Lyon, France.
authors.forename: Wadad
authors.initials: W
authors.lastname: Hassoun
authors.forename: Marion
authors.initials: M
authors.lastname: Le Cavorsin
authors.forename: Nathalie
authors.initials: N
authors.lastname: Ginovart
authors.forename: Luc
authors.initials: L
authors.lastname: Zimmer
authors.forename: Veronique
authors.initials: V
authors.lastname: Gualda
authors.forename: Frederic
authors.initials: F
authors.lastname: Bonnefoi
authors.forename: Vincent
authors.initials: V
authors.lastname: Leviel
mesh_terms: D000777:Anesthetics / Q000494:pharmacology; D000818:Animals; D002415:Cats; D002531:Cerebellum / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism*; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology; D003342:Corpus Striatum / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism*; D006221:Halothane / Q000494:pharmacology; D007649:Ketamine / Q000494:pharmacology; D008297:Male; D020891:Raclopride / Q000493:pharmacokinetics*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed; D014851:Wakefulness / Q000187:drug effects / Q000502:physiology
chemical_list: D000777:Anesthetics; D019275:Radiopharmaceuticals; D020891:Raclopride; D007649:Ketamine; D006221:Halothane