Studies on the origin of rat hippocampal dihydroxyphenylacetic acid using microdialysis.

With a dialysis probe implanted in the rat ventral hippocampus we have monitored effects on noradrenaline (NA) and dihydroxyphenylacetic acid (DOPAC) of the infusion through the dialysis probe of drugs acting at dopaminergic and noradrenergic presynaptic autoreceptors; clonidine and idazoxan produced changes in the extracellular concentration of both NA and DOPAC, whereas LY171555 and sulpiride had no effect on NA but produced changes in the concentration of DOPAC. The combined effect of clonidine and LY171555 on DOPAC was additive. Hippocampal DOPAC is therefore derived from both the noradrenergic and the dopaminergic projection to the hippocampus.