title: Marked Sexual Dimorphism in the Role of the Ryanodine Receptor in a Model of Pain Chronification in the Rat.
abstract: Hyperalgesic priming, an estrogen dependent model of the transition to chronic pain, produced by agonists at receptors that activate protein kinase C epsilon (PKCε), occurs in male but not in female rats. However, activation of second messengers downstream of PKCε, such as the ryanodine receptor, induces priming in both sexes. Since estrogen regulates intracellular calcium, we investigated the interaction between estrogen and ryanodine in the susceptibility to develop priming in females. The lowest dose of ryanodine able to induce priming in females (1 pg) is 1/100,000(th) that needed in males (100 ng), an effect dependent on the activation of ryanodine receptors. Treatment of female rats with antisense to estrogen receptor alpha (ERα), but not beta (ERβ), mRNA, prevented the induction of priming by low dose ryanodine, and the ERα agonist, PPT, induced ryanodine receptor-dependent priming. In vitro application of ryanodine in low concentration (2 nM) to small DRG neurons cultured from females, significantly potentiated calcium release via ryanodine receptors induced by caffeine. This effect was only observed in IB4+ neurons, cultured in the presence of β-estradiol or PPT. Our results demonstrate a profound regulatory role of ERα in ryanodine receptor-dependent transition to chronic pain.
authors: Departments of Medicine and Oral Surgery, and Division of Neuroscience, University of California at San Francisco, 521 Parnassus Avenue, San Francisco, CA 94143, USA.
authors: Luiz F
authors: LF
authors: Ferrari
authors: Departments of Medicine and Oral Surgery, and Division of Neuroscience, University of California at San Francisco, 521 Parnassus Avenue, San Francisco, CA 94143, USA.
authors: Eugen V
authors: EV
authors: Khomula
authors: Departments of Medicine and Oral Surgery, and Division of Neuroscience, University of California at San Francisco, 521 Parnassus Avenue, San Francisco, CA 94143, USA.
authors: Dionéia
authors: D
authors: Araldi
authors: Departments of Medicine and Oral Surgery, and Division of Neuroscience, University of California at San Francisco, 521 Parnassus Avenue, San Francisco, CA 94143, USA.
authors: Jon D
authors: JD
authors: Levine
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D002478:Cells, Cultured; D059350:Chronic Pain; D004305:Dose-Response Relationship, Drug; D047628:Estrogen Receptor alpha / Q000235:genetics*; D047629:Estrogen Receptor beta / Q000235:genetics*; D005260:Female; D006930:Hyperalgesia / Q000139:chemically induced; D008297:Male; D009474:Neurons / Q000378:metabolism; D010147:Pain Measurement / Q000379:methods*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012433:Ryanodine / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism*; D012727:Sex Characteristics
chemical_list: D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D012333:RNA, Messenger; D019837:Ryanodine Receptor Calcium Release Channel; D012433:Ryanodine; D002118:Calcium