Estradiol-induced antinociceptive responses on formalin-induced nociception are independent of COX and HPA activation
| Autor: | Christopher M. Kreiter, Vanya Quinones-Jenab, Nicole Amador, Lynne M. Kemen, Gordon A. Barr, Charles E. Inturrisi, Deirtra Hunter, Shirzad Jenab, Kai-Yvonne Shivers |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Hypothalamo-Hypophyseal System
medicine.medical_specialty medicine.drug_class Ovariectomy medicine.medical_treatment Pain Pituitary-Adrenal System Prostaglandin Pharmacology Article Rats Sprague-Dawley Cellular and Molecular Neuroscience chemistry.chemical_compound Corticosterone Formaldehyde Internal medicine medicine Animals Enzyme Inhibitors Estradiol biology Adrenalectomy Pain Perception Ibuprofen Rats Enzyme Activation Endocrinology Nociception chemistry Prostaglandin-Endoperoxide Synthases Estrogen Irritants Ovariectomized rat biology.protein Female Cyclooxygenase hormones hormone substitutes and hormone antagonists medicine.drug |
| Zdroj: | Synapse. 65:643-651 |
| ISSN: | 0887-4476 |
| Popis: | Estrogen modulates pain perception but how it does so is not fully understood. The aim of this study was to determine if estradiol reduces nociceptive responses in part via hypothalamic-pituitary-adrenal (HPA) axis regulation of cyclooxygenase (COX)-1/COX-2 activity. The first study examined the effects of estradiol (20%) or vehicle with concurrent injection nonsteroidal antiinflammatory drugs (NSAIDs) on formalin-induced nociceptive responding (flinching) in ovariectomized (OVX) rats. The drugs were ibuprofen (COX-1 and COX-2 inhibitor), SC560 (COX-1 inhibitor), or NS398 (COX-2 inhibitor). In a second study, estradiol's effects on formalin-induced nociception were tested in adrenalectomized (ADX), OVX, and ADX+OVX rats. Serum levels of prostaglandins (PG) PGE(2) and corticosterone were measured. Estradiol significantly decreased nociceptive responses in OVX rats with effects during both the first and the second phase of the formalin test. The nonsteroidal antiinflammatory drugs (NSAIDs) did not alter nociception at the doses used here. Adrenalectomy neither altered flinching responses in female rats nor reversed estradiol-induced antinociceptive responses. Estradiol alone had no effect on corticosterone (CORT) or prostaglandin levels after the formalin test, dissociating the effects of estradiol on behavior and these serum markers. Ibuprofen and NS398 significantly reduced PGE2 levels. CORT was not decreased by OVX surgery or by estradiol below that of ADX. Only IBU significantly increased corticosterone levels. Taken together, our results suggest that estradiol-induced antinociception in female rats is independent of COX activity and HPA axis activation. |
| Databáze: | OpenAIRE |
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