AIMTo research the influence of noxious stimuli on the electric activities of pain-related neurons in several subnuclei of Amygdaloid Nucleus in rats.

METHODSTrains of the electric impulses applied to the sciatic nerve were used as noxious stimuli. The discharges of neurons were channeled off by glass microelectrode.

RESULTSPain-related neurons existed in several subnuclei of Amygdaloid Nucleus. When the noxious stimuli were administered the frequency of discharges of pain-excited neurons (PEN) was increased while the frequency of pain-inhibited neurons (PIN) was decreased to the lowest level. The electric activities of PEN and PIN were matched with each other. Intraperitoneal injection of morphine (10 mg/kg) antagonized the effects of noxious stimuli on the pain-related neurons.

CONCLUSIONSeveral subnuclei of Amygdaloid Nucleus play an essential role in perceiving, integrating and transmitting the pain impulses. They are a part of the central nervous system in which pain information is controlled and managed.