Quantitative PET analysis of regional cerebral blood flow and glucose and oxygen metabolism in response to fenfluramine in living porcine brain

The serotonin agonist fenfluramine has been used widely in humans for study ing neuronal activation. We carried out the present study in order to deter mine whether anesthetized pigs could be used for studying effects of fenflu ramine on cerebral functions using positron emission tomography (PET). We o btained quantitative measures of regional cerebral blood flow (rCBF) and of glucose and oxygen utilization (rCMR(glc) and rCMR(O2)) during intravenous administration of fenfluramine, using [O-15]water, [F-18]FDG and [O-15]oxy gen, respectively. Fenfluramine (25 mg/h i.v.) caused a significant rise in rCBF and, to a lesser extent, in rCMR(O2), but it failed to affect rCMR(gl c). The findings indicate that quantitative estimation of rCBF by repeated injection of [O-15]water was more sensitive than either rCMR(O2) or rCMR(gl c) for detecting effects of fenfluramine on serotonin neurotransmission in living porcine brain. (C) 1998 Elsevier Science B.V. All rights reserved.