Zinc is critical for the functioning of all cells. A subset of the zinc in the brain (vesicular zinc) acts as a neurotransmitter and is capable of modulating a variety of receptors. Not all areas of the brain contain vesicular zinc; however, there are high amounts found in the striatum, neocortex, and limbic regions. Some regions have received more attention than others concerning the function of vesicular zinc. Those that have been studied have found that vesicular zinc is important for

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... c plasticity. Less studied regions include areas involved in instrumental conditioning, motivation and reward. A commonly used model to study the role of vesicular zinc is the zinc transporter 3 (ZnT3) knockout (KO) mouse which lack the protein solely responsible for loading zinc into vesicles and thus shows a complete absence of vesicular zinc. The purpose of this thesis was to examine the behaviour of ZnT3 KO mice (compared to wildtype mice) on instrumental conditioning tasks as well as on their response to cocaine. Drugs of abuse, including cocaine, can be used to probe the functioning of the reward pathways. Results found no difference in instrumental conditioning in ZnT3 KO mice. There were, however, differences in response to cocaine which, for the most part, were restricted to one sex or the other. In general, ZnT3 KO mice had reduced locomotor response to cocaine, particularly at higher doses and in females. They also showed differences in "memory" of cocaine experience, with male KO mice more affected. Overall, findings suggest that vesicular zinc is involved in both acute response to cocaine and in the long-term memory of drug-associated cues.