Cerebral cortical blood flow maps are reorganized in MAOB-deficient mice

Cerebral cortical blood flow (CBF) was measured autoradiographically in con scious mice without the monoamine oxidase B (MAOB) gene (KO, n = 11) and th e corresponding wild-type animals (WILD, n = 11). Subgroups of animals of e ach genotype received a continuous intravenous infusion over 30 min of phen ylethylamine (PEA), an endogenous substrate of MAOB, (8 nmol g(-1) min(-1) in normal saline at a volume rate of 0.11 mu l g(-1) min(-1)) or saline at the same volume rate. Maps of relative CBF distribution showed predominance of midline motor and sensory area CBF in KO mice over WILD mice that recei ved saline. PEA enhanced CBF in lateral frontal and piriform cortex in both KO and WILD mice. These changes may reflect a differential activation due to chronic and acute PEA elevations on motor and olfactory function, as wel l as on the anxiogenic effects of this amine. In addition to its effects on regional CBF distribution, PEA decreased CBF globally in KO mice (range -3 1% to -41% decrease from control levels) with a lesser effect in WILD mice. It is concluded that MAOB may normally regulate CBF distribution and its r esponse to blood PEA. (C) 1999 Elsevier Science B.V. All rights reserved.