EFFECTS OF 17-β-ESTRADIOL ON NOCICEPTION IN IMMATURE FEMALE RATS

PURPOSE: Pain transmission involves dynamic and interactive peripheral and central nervous system events and gonadal hormones have been demonstrated to interact with these systems at multiple levels. Estrogens have widespread effects throughout the CNS. Considerable evidence in the literature indicates that they modulate neural circuits known to participate in pain processes. The aim of our study was to investigate the effects of 17-β-estradiol on the pain latention of female rats during the period of prematuration. METHODS: The experiments were carried out on immature female Wistar rats (90g). 17-β-estradiol was administered intraperitoneally once daily for 3 days of the experiment. The changes in the pain latency of the rats were evaluated using tail flick test 4 and 24 hours after injections. RESULTS: The obtained data show that 4 and 24 hours after injection 17-β-estradiol increased significantly TF latency during the whole period of the experiment. CONCLUSIONS: According to our data 17-β-estradiol takes part in the mechanisms of regulation of pain reaction of female immature rats. The effect of the gonadal steroid on pain perception can not be fully explained by the known mechanisms at present. Further studies are needed to clarify the primary site and mechanism of these actions.