ABSTRACT
Objective:The somatosensory evoked cerebral potential (SEP)was used to assess the analgesia effect of clonidine. Method: Twenty-three SD rats was randomly divided into two groups, the control group (n=8) and clonidine group (n=15). The control group rats was injected 1 ml normal saline to peritoneal cavity and the clonidine group rats was injected 10mg(1ml) clonidine peritoneally. The SEP waves were recorded in both groups at preinjection and 20,40,60 min after injection. Pain relief ratio was calculated according to the N15-P25 peak-peak amplitude of SEP wave. Result:SEP amplitude and latency were markedly reduced in clonidine group and remained unchanged in control group. The peak Pain relief ratio was 80. 6％at 20-40 min after clonidine administration. Conclusion:Clonidine does have a effect of pain relief
ABSTRACT
Objective:To investigate the efficacy and characteristics of subarachnoid xenogenetic adrenal medullary transplants on neuropathic pain. Method: Eighty rats were assigned to 4 different groups before their right sciatic nerves were tied according to the method described by Bennet. Each rat received subarachnoidly xenogenetic medullary pieces or isolated chromaffin cells according to the groups. The basal pain thresholds to thermal and electrical stimuli were determined before nerve ligations,and the analgesiometric tests were repeated at weekly intervals following transplantation for 10 weeks. Behavioral indications of spontaneous pain were recorded concomitantly. The effects of naloxone, phentolamine and fentanyl on the antinociception of chromaffin cells were evaluated. Result:The pain thresholds to noxious thermal and electrical stimuli increased after transplantation of medullary pieces or isolated chromaffin cells subarachnoidly. The Behavioral indications of spontaneous pain and hyperalgesia to thermal and electrial were also eliminated after the transplantation. These antinociceptive effects can be reversed by naloxone and phentolamine. Conclusion:Transplanting xenogenetic chromaffin cells into subarachnoid space can reduce neuropathic pain effectively,and this antinociception is conducted via adrenoreceptors and opiate receptors.