Noradrenaline release in the rat amygdala is increased by stress: studies with intracerebral microdialysis

The effects of immobilization and tail-pinch stress on extracellular noradrenaline (NA) release in the amygdala were studied in freely moving rats with intracerebral microdialysis techniques. After collection of basal levels of NA (2.63 +/- 0.26 pg/50 microliters/20 min), the rat was exposed to either immobilization stress or tail-pinch stress for 20 min. Immobilization and tail-pinch stress increased NA release to 250 and 243% of basal levels, respectively and the elevation of NA release was observed for 60 min and 40 min after release from stress, also respectively. These data suggest that microdialysis is a useful way to study extracellular NA release in the amygdala and that NA neurons in this region are activated by both immobilization and tail-pinch stress.