Role of zinc released by stimulation in rat amygdala

The movement and role of actively functioning zinc, i.e., vesicular zinc, i n the amygdala was studied, based on the data that Zn-65 is localized in th e limbic system, which may correspond to the regions with high densities of zinc-containing neuron terminals. When release of Zn-65 into the extracell ular space was examined 2 hr or 25 hr after injection of (ZnCl2)-Zn-65 into the amygdala, Zn-65 release was facilitated by stimulation with high K+ 2 hr after injection, but not 25 hr after injection. Even 25 hr after Zn-65 i njection into the amygdala, approximately 95% of total Zn-65 in the brain w as 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 perfuse d with 10 mu M diethyldithiocarbamate during behavioral tests for odor reco gnition. 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. (C) 1999 Wiley-Liss, Inc.