Our previous work has indicated that excitation of hypothalamic defence area (HDA) could lead to an increase in the release of central monoamine neurotransmitters

pressor and other defence responses.The present experiments showed that stimulation of deep pernneal nerve with a current of low frequency and low intensity could inhibit the pressor

abolish the increase of noradrenaline and its metabolite MHPG and attenuate that of 5-HIAA (a 5-HT metabo-lite)

dopamine and its metabolites DOPAC and HVA in CSF.The data suggest that inputs of deep peroneal nerve may inhibit the increased release of cental monoamine neurotransmitters

and then defence reactions;and inhibition of NA release in some nuclei of the brain is an important mechanism of inhibition of defenee pressor by inputs of deep peroneal nerve.