Effects Of Stimulating The Prefrontal Cortex On The Discharges Of Pain-related Neurons In The Amygdala Of Rabbits And Preliminary Explore Of Probable Mechanism

The purpose of the work was to observe the effects of stimulating the prefrontal cortex on pain-related neurons of amygdala and preliminary explore of probable mechanism in 30 conscious immobilized rabbits. Unit discharges of amygdala(A2~L4.7H15.,8) were recorded extracellularly with glass microelectrode .The electric activities of 254 neurons in the amygdala were observed .There were 114 neurons (pain units )responding to peripheral noxious stimulation, including 53(46.49%) pain excitatory units (PEN) and 61(53.51%) pain inhibitory units (PIN).The nociceptive responses of 90.3 5% pain units also responsed to the PFC stimulation. Of these neurons, 30 PEN (P<0.05) and 35 PIN (P<0.05) altered their spontaneous discharges in responded to noxious stimulation and PFC stimulation in a similar manner . The remainder (18 PEN and 20 PIN )opposited manners. PFC stimulation could alter the responses of amygdala neurons to noxious stimulation. PFC stimulation could enhance or reduce noxious-evoked discharge in amygdala neurons(5 1.25%) which altered their electric discharges in responded to noxious stimulation and PFC stimulation in a similar manner . PFC stimulation could reduce noxious-evoked discharge in amygdala neurons(33.75%) which altered their electric discharges in opposite manners.The two effects of electric stimulating the PFC on noxious- evoked discharge in amygdala neuron were attenuated after haloperidol (n45,P<0.001) or naloxone (n13, P<0.001) was injected into lateral ventricle. And in the saline control group,there was no statistical difference(n10,P>0. 1).The experiment results showed that the PFC can influence the electric activities of pain units in amygdala. Dopamine and Opioid peptides may take part in modulation of the PFC to the nociceptive responses of pain units in amygdala.