Evaluation of the analgesic effects of capsaicin using a new rat model for tonic pain.
An animal model for tonic pain has been produced by means of injecting monosodium urate crystals into a knee joint of rat hind paws in order to evaluate the analgesic effects of various drugs and analgesic methods and to elucidate the physiology of tonic pain. This model allows for stable and long-term behavioural changes due to tonic pain followed by complete recovery without tissue damages. It is advantageous in allowing for objective and quantitative evaluation of the effects of analgesics and should prove useful in research on pain and the development of pain therapy techniques. Using this model, the analgesic effects of capsaicin was evaluated when administered to the neonatal rat or locally to peripheral nerves. In both cases, significant analgesic effects were obtained.
D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D002211:Capsaicin / Q000494:pharmacology / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D008297:Male; D009020:Morphine / Q000627:therapeutic use; D010146:Pain / Q000188:drug therapy*; D051381:Rats; D011919:Rats, Inbred Strains
D000700:Analgesics; D009020:Morphine; D002211:Capsaicin