Inflammation of the colonic wall induced by formalin as a model of acute visceral pain.
Acute inflammation of the sigmoid wall was induced by perendoscopic injection of formalin (50 microliters, 5%) under brief anesthesia in rats. The procedure was followed by behavioral patterns that significantly differed from those in animals injected with isotonic saline instead of formalin. Analysis of the formalin-induced behaviors allowed for the calculation of a pain score that evolved in a biphasic manner along the 3 h of test. The score was dose-dependently reduced by morphine (0.5-4 mg/kg), and the analgesic effect of the largest morphine dose was abolished by naloxone (2.4 mg/kg). These results suggest that formalin into the sigmoid colon is a new model of visceral pain, presumably through direct irritation at injection site and/or localized acute inflammation of the intestinal wall.
Miampamba
Marcel
M
INSERM Unité de Recherches de Physiopathologie Digestive (U45), Pavilion H bis, France URA CNRS 1447 Laboratoire de Physiologie Sensorielle, Audition et voix, Pavilion U France Service d'Anatomie Pathologique, Hôpital Edouard Herriot, 69437 Lyon cedex 03 France.
Chéry-Croze
Sylviane
S
Gorry
Fabien
F
Berger
Françoise
F
Chayvialle
Jean-Alain
JA
D000208:Acute Disease; D000818:Animals; D003092:Colitis / Q000139:chemically induced* / Q000503:physiopathology; D004195:Disease Models, Animal; D005260:Female; D005557:Formaldehyde; D009020:Morphine / Q000627:therapeutic use; D009270:Naloxone / Q000627:therapeutic use; D010146:Pain / Q000503:physiopathology; D010147:Pain Measurement; D010166:Palliative Care; D051381:Rats; D017207:Rats, Sprague-Dawley; D012965:Sodium Chloride; D014781:Viscera
D005557:Formaldehyde; D009270:Naloxone; D012965:Sodium Chloride; D009020:Morphine