The importance of striatal interneurons in age-related effects upon potassium- and amphetamine-stimulated dopamine release.

The ability of superfused corpus striatal tissue fragments to release endogenous dopamine (DA) in response to potassium (K+ 30 mM) stimulation was significantly attenuated in 18- to 24-month- compared to 2- to 4-month-old male rats. These age-related effects on K+ stimulation were completely abolished with the addition of tetrodotoxin (1 microM) to the superfusion medium. Moreover, no difference in stimulated DA release was obtained between these two age groups following amphetamine stimulation (10 microM).