Effects of tramadol on viscero-visceral hyperalgesia in a rat model of endometriosis plus ureteral calculosis.

Abstract

The effects of tramadol versus placebo administration on behavioral indicators of ureteral pain, pelvic pain and referred lumbar muscle hyperalgesia were investigated in a rat model of viscero-visceral hyperalgesia from endometriosis plus ureteral calculosis (endo + stone). Fifty female Sprague-Dawley rats underwent surgical induction of endometriosis and, 2 weeks later, were randomly assigned to five groups (10 each), to be treated i.p., twice a day, with tramadol (0.625, 1.25, 2.5, or 5 mg/kg) or saline for 5 days (14-18th day postendometriosis; prestone treatment). On the 21st day, they underwent laparotomy for stone formation in the upper left ureter (dental cement injection). All were video-taped 24 h nonstop for 7 days before and 4 days after stone formation (14-25th day postendometriosis) to record ureteral and pelvic pain behaviors. Lumbar sensitivity (L1) was tested bilaterally, daily over the same period, by verifying presence/absence of vocalization upon muscle pinching at a predefined pressure (calibrated forceps). Additional fifty endo + stone rats underwent the same protocol, except that treatment was performed on 21st-25th day (poststone treatment). Tramadol vs. saline significantly reduced number and duration of ureteral crises, duration of pelvic behavior, and incidence of muscle hyperalgesia (P < 0.0001), with a dose-dependent effect. Prestone treatment was significantly more effective than poststone treatment for the 1.25 dose for all parameters and 2.5 dose for pelvic and muscle parameters (0.003 > P < 0.02). Tramadol, even at low doses, is thus highly protective against pain from 'viscero-visceral hyperalgesia' in endometriosis plus ureteral calculosis; it can represent a valid therapeutic approach in women with these comorbidities.

• Authors: Mariangela Lopopolo, Giannapia Affaitati, Alessandra Fabrizio, Francesca Massimini, Domenico Lapenna, Maria Adele Giamberardino, Raffaele Costantini
• Journal: Fundamental & clinical pharmacology (Fundam Clin Pharmacol) Vol. 28 Issue 3 Pg. 331-41 (Jun 2014) ISSN: 1472-8206 [Electronic] England
• PMID: 23786290 (Publication Type: Journal Article)
• Copyright: © 2013 The Authors Fundamental and Clinical Pharmacology © 2013 Société Française de Pharmacologie et de Thérapeutique.

Chemical References

• Analgesics, Opioid
• Tramadol

Topics

• Analgesics, Opioid (administration & dosage, pharmacology, therapeutic use)
• Animals
• Behavior, Animal (drug effects)
• Disease Models, Animal
• Dose-Response Relationship, Drug
• Endometriosis (complications, drug therapy)
• Female
• Hyperalgesia (complications, drug therapy)
• Rats, Sprague-Dawley
• Tramadol (administration & dosage, pharmacology, therapeutic use)
• Ureteral Calculi (complications, drug therapy)
• Visceral Pain (complications, drug therapy)