[The role of amygdala in the inhibitory effect of somatic afferent inputs on the central pressor response].

AIM

To investigate the inhibitory effect of the deep peroneal nerve (DPN) on the cardiovascular responses induced by excitation of the paraventricular nucleus of hypothalamus (PVN) and the role of central nucleus of amygdala (CeA) in this effect.

METHODS

CeA was injected by L-glutamate or Kainic acid (KA). The femoral arterial pressure, mean arterial pressure (MAP), electrocardiogram (ECG) and heart rate (HR) of SD rats were recorded while PVN or DPN was electrically stimulated.

RESULTS

It showed that MAP increased when PVN was activated by electrical stimulation. Stimulating contralateral DPN inhibited this pressor response. Ten minutes after microinjection of KA(0.02 mol/L, 100 nl) into ipsilateral CeA, MAP increased for (13.8 +/- 3.2) mmHg when PVN was stimulated. Microinjection of KA into CeA could not only reduce the pressor response elicited by stimulation of PVN for (6.6 +/- 1.6) mmHg (P < 0.05), but also the inhibitory effect of DPN from 51.5% to 32.0% .

CONCLUSION

The results suggest that central nucleus of amygdala partly mediate the central pressor response induced by stimulation of PVN. The neurons in central nucleus of amygdala are involved in the inhibitory effect of DPN on the above pressor response.