Repeated methamphetamine treatment increases expression of TRPV1 mRNA in the frontal cortex but not in the striatum or hippocampus of mice.

The transient receptor potential vanilloid type 1 (TRPV1) is a non-selective ligand-gated cationic channel. The distribution of TRPV1 mRNA in various regions of the brain has been successfully established. Methamphetamine (MAP) is a psychostimulant and a major drug of abuse in many parts of the world. The powerful rewarding properties of MAP are attributed to multiple pharmacological actions, but the mechanistic association between TRPV1 expression and MAP-induced drug addiction has not established. In the present study, we conducted a time-course analysis of TRPV1 mRNA levels in the frontal cortex, striatum, and hippocampus of mouse brain following repeated MAP (2mg/kg, i.p.) treatment. Our results demonstrate that expression of TRPV1 mRNA is significantly increased 1, 2, 6, 24, 48h, and 1 week after the last MAP treatment in the frontal cortex but not in the striatum or hippocampus. These data support a potential role for TRPV1 in the treatment of MAP-induced drug addiction.