THE EFFECT OF SELENIUM ON THE CENTRAL DOPAMINERGIC SYSTEM - A MICRODIALYSIS STUDY

The effects of Selenium(Se) on central dopaminergic function were exam ined in male Sprague-Dawley rats. In this experiment, animals were imp lanted with microdialysis probes and dialysates were analyzed for dopa mine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic aci d (HVA). After reaching baseline values, sodium selenite was either in jected intraperitoneally (i.p.) or directly infused into the striatum (ST) or nucleus accumbens (NA). Se administration of 3.0 mg/kg (i.p.) significantly increased (70%) DA overflow in the ST. Meanwhile direct Se perfusion (10 mM) also caused a significant elevation of synaptic D A concentrations in the ST and NA. Levels of DOPAC and KVA were minima lly affected in all studies. In order to test for the effects of DA re ceptor activation, animals were pretreated with quinpirole (0.5 mg/kg, s.c.), an hour prior to Se (10 mM) infusion through the probe. It was found that quinpirole pre-treatment reduced Se-induced changes in DA concentrations. It was concluded from the present study that Se's cent ral action might be related to its ability to potentiate DA function.