Our experiments showed that analgesic electroacupuncture (EA: 8c/s

3V) had a pressor effect in conscious paralysed male rats under artificial respiration. The pressor effects of "Zusanli--Sanyingiao" and "Quchi-Neigu- an" were statistically different

suggesting that the effects of different acu- points were relatively specific. There was no significant difference betwe- en effects of different EA parameters used. In further experiments

ele- ctrostimulation of A_1 (or A_5

locus coeruleus) or microinjection of sodium glutamate into locus coeruleus produced a marked rise in blood pressure

but the pressor effect of EA remained unchanged after bilateral lesions of A_1 or A_5 nuclei. Thus

it is liKely that A_1 and A_5 areas do not play an- important role in pressor effect of EA. On the contrary

the pressor effect of EA was abolished by bilateral lesions of locus coeruleus

indica- ting that locus coeruleus (A_6) plays a critical role in pressor effect of EA.