Simultaneous detection of monoamines in rat striatal microdialysate at poly(para-aminobenzoic acid) modified electrode by high-performance liquid chromatography

In this paper, poly(para-aminobenzoic acid (p-ABA)) (P-pABA) electrochemically modified glassy carbon electrode (GCE) was prepared. The electrochemical behavior of monoamine transmitters and their metabolites at this P-pABA modified electrode have been studied by cyclic voltammetry (CV). The results indicated that the modified electrode exhibited efficiently electrocatalytic oxidation for neurotransmitters and their metabolites with relatively high sensitivity, stability, and long-life. Coupled with high-performance liquid chromatography (HPLC), the P-pABA modified electrode was utilized for electrochemical detection (ECD) of these compounds. The linear ranges were over three orders of magnitude and the detection limits were 5.0 × 10^-9 moll^-1 for norepinephrine (NE) and epinephrine (E), 2.0 × 10^-8moll^-1 for dopamine (DA), 3,4-dihydroxyphenyl acetic acid (DOPAC), serotonin (5-HT), 5-hydroxylindole acetic acid (5-HIAA) and homovanillic acid (HVA), respectively. The method has been successfully applied to assess the contents of monoamines and metabolites in rat brain microdialysates. To study the physiological function of nitric oxide (NO) on striatal DA release, a continual perfusion of 3.0 × 10^-5 moll^-1 sodium nitroprusside (SNP) was performed into rat striatum, which increased striatal DA release with 1.5-fold to the basal level.