Protective effects of isoliquiritigenin against methamphetamine-induced neurotoxicity in mice

Abstract

Isoliquiritigenin (ISL) suppresses cocaine-induced extracellular dopamine levels and has a neuroprotective effect in cocaine-treated rat brain. Here, we examine the effect of ISL on methamphetamine-induced striatal neurotoxicity. Repeated injections of methamphetamine cause the loss of striatal dopamine transporter (DAT) and tyrosine hydroxylase (TH). Intraperitoneal injection of ISL prior to methamphetamine injection significantly prevented methamphetamineinduced reduction of DAT and TH. ISL also suppressed methamphetamine-induced activation of glial cells. Moreover, ISL impeded the expression of nitric oxide synthase and the activation of NF-κB through blockage of its phosphorylation. Our results suggest that ISL protects against methamphetamine-induced neurotoxicity by inhibition of NF-κB activation. ©2009 The Japanese Pharmacological Society.