HPLC-EC analysis of catechols and indoles in rat brain dialysates

This short article reviews HPLC-EC methodology that we are currently applying to measure DA, 5-HT and their acid metabolites in rat brain dialysates collected in vivo. HPLC-EC systems based on standard-bore HPLC columns are described which are sufficiently sensitive to allow detection of the monoamine transmitters and their metabolites in regional brain dialysates collected at 10-20 min intervals. A large reduction in sample requirement was achieved by "down-scaling" the conventional HPLC-EC assay to incorporate small-bore HPLC columns. The small-bore systems allowed monoamines to be detected in samples collected over 1 to a few minutes.