Tremorgenic neuromycotoxicosis caused by extrolites from several Penicillium species (e.g.Penicillium crustosum) is an important syndrome in domestic animals.The potential hazard to humans remains unclear,although there have been a few documented cases.We have lately reported the accidental intoxication of six dogs suspected poisoned by the tremorgenic mycotoxin penitrem A,a secondary metabolite produced by Penicillium crustosum.Either Penicillium crustosum or penitrem A were detected in samples from all the cases studied.To our.knowledge,this is the first time the presence ofpenitrem A has been reported in organs from poisoned animals,especially in brain and liver.Following these findings and based on the onset of the cases reported we have conducted a study to determine the metabolic biotransformation of the neurotoxin as well as the possible involvement of the GABA-ergic and the glutamatergic systems in the central nervous system (CNS).The metabolism of penitrem A has been evaluated in vivo by p.o.administration to mice and in vitro after incubation with rat hepatocytes and microsomes.