In this year, we were focused on two major sub-projects. First, using high-speed monitoring of EEG and EMG in freely moving rats, we demonstrated that intravenous (iv)nicotine induced rapid cortical and VTA EEG desynchronization and motor activation that occur within the time-course of injection. We also showed that a similar rapid response could be elicited by both nicotine-pirrolidine methiodide that cannot cross the blood-brain barrier. The nicotine-induced electrophysiological effects were strongly attenuated by hexamethonium, a blocker of peripheral nicotinic receptors. Therefore, it appears that rapid activation induced by iv nicotine is triggered via activation of peripheral neural substrates. We also show that the peripherally triggered effects of nicotine are conditioned and peripherally acting nicotine analogue induces conditioned behavioral and neural activation. The second sub-project, which was initiated during this year, is focused on reliable detection of glutamate (GLU) in the brain of freely moving rats. Currently, we are working to resolve several technical problems related to the use and performance of enzyme-coated electrochemical electrodes. We also examined changes in GLU levels following exposure to various environmental stimuli and intravenous cocaine. This work will be expanded during the next years to include other detected substances and the use of more complicated behavioral paradigms that involve the use of addictive drugs.
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