RESUMO
Stress can disturb the physiological homeostasis and the ability to cope with such stressful insults is crucial determinant factor in people health. Today with advances in technology social stresses are increasing. Pain threshold as one of the important physiological systems is affected by stress. Stress induced analgesia is well documented, however, in some situations stress causes hyperalgesia. Type of stress, duration and intensity of stress are major factor in determining hyperalgesia or analgesia. Present study was design to investigate the role of sex and age on pain threshold changes after social conflict stress in rats. Survey the Effect of Age and Gender on Hypreralgesia Induced by Social Conflict Stress in Rats. In this study 60 wistar rats including young [3 months] and old [28 months] were selected for studding the role of stress on pain threshold. Ten young rats were overectomized and 10 rats went under sham operation .Pain latencies were measured using Tail-Flick apparatus before and after stress. The time lapsed that rats moved their tail from photo cells was recorded as tail-flick latencies. Stress was induced by making 4 holes on each side of rats cage and fixing rats tail to the outside of the cage after passing and fixing their tail through the holes. Rats were stressed for ten days, each time for 2 hours. Before stress there was no difference in pain latencies among male and female rats [p>0.05]. On the other hand old rats showed higher pain latencies than young rats [p<0.001]. Overectomized rats showed significant reduction in pain latencies compared to sham operated group [p<0.05]. After stress in all groups old, young, female and overectomized tail flick latency significantly decreased [p<0.05 and p<0.01]. Reaction to stress in both sexes was comparable, while reduction in tail flick latency was more in overectomized rats compared to sham operated group [p<0.01]. Old rats showed more reduction in tail flick latency compared to young rats. [p<0.01] Social conflict stress cause hyperalgesia in rats. It seems old rats and overectomized are sensitive to social conflict stress and showed more hyperalgesia