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Abstract: (13477 Views)
Background: The role of sex hormones in pain perception and the effect of stress on reproductive system have not been determined yet. The present study investigated the effects of acute and chronic restraint stress on nociception and sex hormones concentration in rats. Methods and Materials: This experimental study was carried out with 47 male and female rats which ranged in weight from 170-230 gr. In order to transmit stress to the rats, they were initially exposed to acute restraint stress (1h) and chronic stress (for two weeks-1h/day). Then they were submitted to tail flick test for nociception evaluation. Sex hormones serum level was measured by radioimmunoassay method. Results were analyzed with Mann-Whitney and Kruskal-Wallis tests. Results: In male and female rats, acute restraint stress had significant increment in latency in the tail flick test. Chronically stress in male rats, was not significant effect on latency time. Chronically stress in females responded to restraint stress with an increase in tail flick latency. Both acute and chronic restraint stress reduced testosterone level in the male rats. In the female rats, only acute restraint stress significantly decrease plasma estradiol level. Restraint stress did not effect on testosterone concentration level in the female and estradiol level in the male rats. Conclusion: Acute restrain stress decrease nociceptive and sex hormon levels in male and female rate but, chronic restraint stress causes sex dependent response.
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General Received: 2009/06/23