Local Drug Infusions to the site of Voltammetric Measurement of Dopamine in the Nucleus Accumbens (2015)
Undergraduates: Eleanor Brightbill, Leslie Wilson Tatiana Shintko, Donita Robinson, Leslie Sombers
Faculty Advisor: Donita Robinson
Department: Chemistry
The role of the brain dopaminergic (DA) system in mechanisms of reward-based learning and addiction is widely studied with fast-scan cyclic voltammetry (FSCV) in behaving and anesthetized animals. This system is regulated by many different receptors including D2 autoreceptors, mu- kappa- and delta- opioid receptors, and GABA receptors. However, little is known about specific somatodendritic and axonal sites of the receptor actions on DA release. Drug application focused on a specific brain region rather than systemic injections allow for detailed study of the mechanisms of the DA system. Therefore, in this study, we investigated whether drugs affecting DAergic neurotransmission can be infused in the axonal site of DA neurons using an infusion cannula, while DA release is measured with FSCV. We evaluated effects of nomifensine (NOM) and vehicle locally applied to the side of DA recording on the dynamic of evoked DA release and uptake in the nucleus accumbens (NAc) of anesthetized rats.
Male Long-Events rats were used in this study. DA efflux was measured with FSCV and NOM was dissolved in saline and infused to the NAc at a concentration of 20 ¿¿M at rate of .25 ¿¿L/min for 2 min. DA release in the NAc was induced by electrical stimulation delivered in the VTA. Effect of the drug on [DA], Vmax and Km were evaluated using Michaelis-Menten kinetic method and compared to vehicle using two-way RM ANOVA.