INCREASED EXTRACELLULAR DOPAMINE IN THE NUCLEUS-ACCUMBENS OF THE RAT ELICITED BY A CONDITIONAL STIMULUS FOR FOOD - AN ELECTROCHEMICAL STUDY

Stearate-modified graphite paste electrodes were implanted chronically into dopamine terminal regions in the nucleus accumbens or caudate nu cleus of the rat. Reverse dialysis was used to demonstrate a selective response of these electrodes to dopamine, but not 3,4-dihydroxyphenyl acetic acid or ascorbic acid. In a separate behavioural experiment, a significant increase in the chronoamperometric response was observed d uring presentation of a conditional stimulus predictive of food, and t he electrochemical response remained elevated during and following con sumption of the meal. Similar trends were observed from electrodes in the caudate nucleus. These data confirm the activation of mesolimbic d opamine neurons by incentive stimuli predictive of food and possibly b y consumption of food. Together with other recent data on sex- and thi rst-related increases in dopamine levels in the nucleus accumbens, the se findings are consistent with a role for the nucleus accumbens as an interface between motivation and activation of the motor system.