We took the unit discharges of the neurons in the posterior group of thala-mic nuclei (PO) caused by stimulating the great splanchnic nerve (GSN) as anindicator of visceral pain.We searched for the effects of eletrical stimulatingcentral nucleus of amygda(?)a (AC)

lateral nucleus of amygdala (AL)

bed nucle-us of striae terminalis (BNST) and lateral area of hypothamus (AHL) on unitdischarges of PO and the relationship among these nucleuses.The result indicated that the inhibitory effects were strongest with stimula-ting AC

the next was with stimulating AHL

then BNST and AL.The inhibi-tory percentages were 85.7%(AC)

62.9%(AHL)

53.1% (BNST) and 54.2%(AL) respectively.The inhibitory effects of stimulating AC couldn't be cance-led by injecting naloxone intravenously.AC may be more important for theantinociceptive system than AL

BNST and AHL.There was no relationshipbetween AC and BNST on the inhibition of unit discharges.The inhibitoryeffects of stimulating AL may be related to AC.