Role of zinc released by stimulation in rat amygdala

The movement and role of actively functioning zinc, i.e., vesicular zinc, in the amygdala was studied, based on the data that 65Zn is localized in the limbic system, which may correspond to the regions with high densities of zinc-containing neuron terminals. When release of 65Zn into the extracellular space was examined 2 hr or 25 hr after injection of 65ZnCl2 into the amygdala, 65Zn release was facilitated by stimulation with high K+ 2 hr after injection, but not 25 hr after injection. Even 25 hr after 65Zn injection into the amygdala, approximately 95% of total 65Zn in the brain was detected in the injected area. These results suggest that zinc released into the extracellular space in the amygdala is not readily restored to the presynaptic vesicles. Moreover, to chelate zinc in the extracellular space (and in the synaptic vesicles) in the amygdala, the amygdalae were perfused with 10 microM diethyldithiocarbamate during behavioral tests for odor recognition. The olfactory sensation was temporarily disturbed by the perfusion. These results suggest that vesicular zinc is essential to the function of the amygdala, e.g., olfactory function.