| Abstract: | Effects of stimulation of the locus coeruleus (LC) on evoked potential in the medial amygdala elicited by stimulation of the olfactory bulb (OB-AME potentials) were studied in the gallamine-immobilized rats. The amplitude of the OB-AME potential was inhibited 27.5% by the conditioning stimulation of LC delivered 30 msec before the test stimulation. The inhibitory effect of LC was reduced by propranolol 5 mg/kg i.p., but not by phentolamine 10 mg/kg i.p.. This effect was also reduced by tetrabenazine 10 mg/kg i.p.. Methamphetamine 5 mg/kg i.p. produced considerable potentiation of the LC inhibitory effect and a reduction of the OB-AME potential itself. These results suggest that the LC plays an inhibitory role in the electrical activity of the medial amygdala. |
