The ability of methamphetamine to inhibit the firing rate of dopamine cells in the substantia nigra pars compacta (SNC) and the ventral tegmental area (VTA) was studied. Methamphetamine reduced the firing rates of the dopamine cells in a dose-dependent manner in the SNC and the VTA. The doses of methamphetamine required to produce a 50% inhibition of firing rate in the SNC and the VTA were 0.37 mg/kg and 0.28 mg/kg, respectively.
