Effects of substance P on extracellular dopamine in neostriatum and nucleus accumbens.

Microdialysis was used to monitor changes in dopamine release in the neostriatum and nucleus accumbens after peripheral administration of substance P in freely moving rats. Substance P in a dose of 50 micrograms/kg produced a steady moderate increase in dopamine levels in the neostriatum, which persisted for at least 5 h. In contrast, a dose of 250 micrograms/kg caused an acute increase in dopamine levels in the nucleus accumbens, which lasted about 2 h. These data suggest that the peripheral administration of substance P can influence dopamine release in mesolimbic and mesostriatal terminals.