ENDOGENOUS DOPAMINE OUTFLOW FROM RAT STRIATAL SLICES IN STATIC AND DYNAMIC CONDITIONS

Endogenous dopamine (DA) outflow from rat striatal slices was monitore d in static or dynamic conditions. Tissue was superfused (0.2 ml/min) (SUP) with, of sequentially incubated (1 ml for 5 min) (SEQ) in, buffe r containing various agents. DA and its metabolite, 3,4-dihydroxypheny lacetic acid (DOPAC), were quantified by HPLC with electrochemical det ection. KCl (25, 50 and 75 mM), veratridine (25 mu M) and 4-aminopyrid ine (100 mu M) increased DA outflow in both methods. Tetrodotoxin (1 m u M), calcium-free buffer and alpha-methyl-para-tyrosine (50 mu M) dec reased DA outflow under SUP and SEQ conditions. The DA antagonist (-)s ulpiride (1 mu M) had no effect, whereas the DA uptake inhibitor GBR 1 2909 (0.5 mu M) increased DA outflow. Only a few treatments induced mo difications in DOPAC outflow, but the pattern was dissimilar ar in the two methods. In conclusion, when DA outflow is considered, dynamic an d static incubation conditions lead to similar responses. However, dif ferences in DOPAC outflow suggest that the dynamics of neurotransmitte r presynaptic stores could differ in some instances in SEQ and SUP.