Long-term ovariectomy changes formalin-induced licking in female rats: the role of estrogens

Reproductive Biology and Endocrinology

Anna Maria Aloisi¹  Cosimo Massafra¹  Paolo Fiorenzani¹  Ilaria Ceccarelli¹ 

[1] Department of Physiology, Section of Neuroscience and Applied Physiology, University of Siena, via Aldo Moro, 53100 Siena, Italy

关键词: Ovariectomy;    Formalin Test;    Plantar Test;    Pain;    Gonadal hormones;   

Others  :  1156984
DOI  :  10.1186/1477-7827-1-24

 received in 2003-01-24, accepted in 2003-02-14,  发布年份 2003

【 摘 要 】

Gonadal hormones have been shown to exert modulatory effects on nociception and analgesia. To investigate the role of gonadal hormones in the response by female rats to both phasic and persistent nociceptive stimulation, we evaluated the effects of long-term ovariectomy (OVX, 6 months) on the thermal pain threshold and on formalin-induced responses. The thermal pain threshold was evaluated with the plantar test apparatus, while persistent pain was induced by a subcutaneous injection of dilute formalin (50 microliter, 10%) in the dorsal hind paw. The formalin test was carried out in an open field apparatus where the animal's spontaneous behavior and formalin-induced responses (licking duration, flinching frequency and flexing duration of the injected paw) were recorded for 60 min. Estradiol and corticosterone plasma levels were determined in blood collected from the anesthetized animals at the end of the test. In OVX females, the duration of formalin-induced licking was longer than in Intact females during both the first and the second phase; flinching and flexing did not differ from Intact. The thermal pain threshold was only slightly affected by OVX. Estradiol and corticosterone were lower in OVX females than Intact ones. These data indicate that long-term depletion of gonadal hormones in female rats modulates the pain-induced behavioral responses related to supraspinal neural circuits (licking of the injected paw) rather than more spinally mediated responses such as formalin-induced flinching and withdrawal latency in the plantar test.

【 授权许可】

   
2003 Ceccarelli et al; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL.

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