Dopamine releasing actions of NMDA in rat caudate putamen studied by fast cyclic voltammetry

Investigations in vitro (Clow & Jhamandas, 1989; Krebs et al., 1990) have shown that glutamic acid, acting at NMDA receptors in the absence of Mg²⁺ can stimulate the release of dopamine (DA) from nerve terminals in the rat caudate putamen (CPu). We have investigated the actions of NMDA on DA release and on DA overflow evoked by local electrical stimulation in caudate putamen slices in presence or absence of Mg^2+. Experiments were made in 350 $&m coronal slices of rat CPu (0.7-1.7mm anterior to bregma;Paxinos & Watson, 1982). DA overflow following single pulse electrical stimulation (0.1 Ims; 20 v) or addition of drugs to the perfusion medium was monitored by fast cyclic voltammetry at a carbon microelectrode, implanted 60-80 jum inside the slice using methods described by (Palij et al. 1990).