Changes in amygdaloid afterdischarges and kindling effect following olfactory bulbectomy in the rat.

Changes in the thresholds for afterdischarges and the formation of kindling effect in the medial amygdala following olfactory bulbectomy were investigated in the rat with chronic electrode implants. The threshold for afterdischarges in the amygdala of the olfactory bulbectomized rat (OB rat) was significantly decreased on day 4 after olfactory bulbectomy, however, no significant difference was found between OB and sham operated rats on days 7, 14 and 21 since the threshold in the sham group was also decreased at these periods after the surgery. The formation of kindling effect was remarkably accelerated in the OB rats. In this case, the number of days required to reach the stage 1 (Racine's classification) was significantly shortened. These results suggest that the activity of the medial amygdaloid nucleus is increased following olfactory bulbectomy.