[Pharmacokinetic behavioral changes of methamphetamine in methamphetamine-sensitized animal model]

There has been an increased population of users and abusers of amphetamines, including methamphetamines (METH), in the past two decades, and this has become a crucial social problem in Japan. METH abusers show a paranoid schizophrenia-like syndrome, including paranoid hallucination and delusion, and repeated exposure to these drugs will enhance their effects; i.e. the behavioral and reinforcing effects of abusing drugs became progressively and irreversibly developed (behavioral sensitization) in humans and in experimental animals. Although numerous neuropsychopharmacological/neurochemical studies on behavioral sensitization were conducted, few reports are available to understand the pharmacokinetic aspect of METH, including the brain penetration of METH, in this phenomenon. The present report reviews previous pharmacokinetic studies for METH and our findings in rats having behavioral sensitization to METH, especially from the point of view regarding the relationship of drug transporters.