AN IMPROVED METHODOLOGY FOR ROUTINE IN-VIVO MICRODIALYSIS IN NONHUMAN-PRIMATES

A new method was developed to carry out in vivo microdialysis experime nts repetitively and routinely within an individual monkey. We designe d and built a dialysis probe guide and holding device ('guide holder') which permits accurate placement of dialysis probes into cortical (e. g., prefrontal, hippocampus, and parietal cortices) and subcortical ta rget areas (e.g., caudate nucleus, amygdala, and nucleus accumbens) of the rhesus monkey brain without extensive and repetitive surgery need ed to expose a desired brain region. The guide holder is positioned, u sing MRI-guided coordinates, and fixed to the skull over an intended t argeted region. This design provides an opportunity to conduct several experiments in a single monkey over an extended period and permits pl acement of several probes accurately into 'fresh' or 'experienced' tis sue during repeated microdialysis experiments. In addition, during rep eated dialysis experiments tissue trauma is minimized because no surgi cal procedure is necessary on the day of dialysate collection. This pr ocedure can be readily adapted for use with an awake monkey.