Lamotrigine blocks apoptosis induced by repeated administration of high-dose methamphetamine in the medial prefrontal cortex of rats

Lamotrigine (LTG) is sometimes co-administered with antipsychotic drugs for the treatment of schizophrenia. Nevertheless, the pharmacological basis of LTG use for schizophrenia has not been reported. Our group recently proposed a new psychostimulant animal model that might reflect the progressive pathophysiology of schizophrenia. Results obtained using that model show that LTG blocks the initiation and expression of repeated high-dosage methamphetamine-induced prepulse inhibition deficit in rats (Nakato et al., 2010, Neurosci. Lett. [25]). Using the model, the effect of LTG (30 mg/kg) on methamphetamine (METH, 2.5 mg/kg)-induced increases in extracellular glutamate levels in the medial prefrontal cortex (mPFC) was examined in this study. Then the effect of repeated co-administration of LTG (30 mg/kg) on repeated METH (2.5 mg/kg)-induced apoptosis in this region of rats was investigated. Results show that LTG (30 mg/kg) blocked the METH (2.5 mg/kg)-induced glutamate increase in the mPFC. Repeated co-administration of LTG (30 mg/kg) blocked the development of apoptosis induced by repeated administration of METH (2.5 mg/kg) in the mPFC. The LTG blocks histological abnormalities induced by repeated administration of METH, which suggests a mechanism of LTG that protects against progressive pathophysiology in schizophrenia.

Research highlights▶ Apoptosis plays an important role in progressive cortical atrophy in schizophrenia. ▶ Methamphetamine (METH) induced apoptosis in the medial prefrontal cortex (mPFC). ▶ METH increased extracellular glutamate levels in the mPFC. ▶ Lamotrigine (LTG) prevented these changes induced by METH in the mPFC. ▶ LTG may prevent longitudinal pathophysiological development in schizophrenia.