In vivo simultaneous monitoring by Pt-disk microelectrodes of intracerebral hydrogen peroxide and dopamine in rats

A technique was developed for simultaneous monitoring of temporal changes i n hydrogen peroxide (H2O2) and dopamine (DA) levels by using Pt-disk microe lectrodes ( phi 30 mu m). H2O2 and DA were determined by differential doubl e-pulse amperometry (for H2O2; 1st step, 750 mV, 1000 ms; 2nd step, 1100 mV , 1000 ms: far DA; 1st step, 150 mV, 600 ms; 2nd step, 250 mV, 50 ms). The electrode for H2O2 or DA is capable of determining each target substance an d these substances do not interfere with each other. For an in vivo applica tion, the electrodes were implanted into the striatum of rats and used succ essfully to monitor intrastriatal changes in H2O2 and DA simultaneously aft er intraperitoneal injection of methamphetamine while the animals were movi ng freely.