In Vivo Release of Dopamine by Perfusion of 1-Methyl-4-Phenylpyridinium Ion in the Striatum with a Microdialysis Technique

We examined the effects of 1-methyl-4-phenylpyridinium ion (MPP+) on the release of DA in rat striatum by the in vivo microdialysis technique. For this study, we made a suitable microdialysis probe from a 22-G needle, microliter pipette tip, silica tube and polyethylene tube. Such a repairable microdialysis probe can be easily made from readily available and inexpensive materials. DA release, as determined by the 3-methoxytyramine level, was dose-dependently increased by MPP+ (1–10 mM). Only the presence of a 1 mM concentration of MPP+ in the dialysate significantly decreased the level of the DA metabolite DOPAC, while administration of higher MPP+ concentrations resulted in no significant change.