Potentiation of inputs from the posterolateral amygdala to the dentate gyrus and resistance to stress ulcers formation in rats

Physical restraint was found to increase the activity of a number of multiple units in the lateral amygdala of rats. High-frequency electrical stimulation of units in the posterolateral amygdala increased the amplitudes of granule cell potentials in the dentate gyrus. This bilateral long-term potentiation (LTP) of inputs from posterior areas of the lateral amygdala also attenuated the severity of stress ulcers produced by physical restraint. This effect was reversed by intraventricular injections of the selective N-methyl-D-aspartate receptor blocker, aminophosphonovaleric acid. LTP in this pathway also reduced “struggling” behavior during restraint. The data were interpreted to indicate that LTP in this temporal lobe pathway increased the coping ability because of faster habituation to stressors.