Tail-flick latency and self-mutilation following unilateral deafferentation in rats.
Unilateral deafferentation induced by transection of the C(4)-C(8) dorsal roots of spinal cord, followed by a complex of abnormal self-mutilating behavior, is interpreted as an animal model of chronic nociception. The objective of our study was to test the differences in tail-flick latency between intact control and unilaterally deafferented animals and to assess the changes in their acute nociceptive sensation. The initial hypothesis was that deafferentation-induced painful sensation might cause stress-induced analgesia that should be manifested as prolonged tail-flick latency. The experiment was carried out on 11 male and 10 female adult Wistar rats. The tail-flick latency was repeatedly measured over a period of 10 consecutive weeks both in the preoperative baseline period and following multiple cervical dorsal rhizotomy. Contrary to our hypothesis, unilateral deafferentation was followed by a significant shortening of the tail-flick latency both in males and females. In deafferented animals, compared to the controls, variations of tail-flick latency were reduced. In individual animals after deafferentation, concurrent dynamic changes were observed in self-mutilating behavior, in a loss and regaining of body weight, and in tail-flick latency. Our data suggest that changes in tail-flick latency may be interpreted in terms of central sensitization and that tail-flick latency might be considered as a useful marker of chronic nociception.
Kríz
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N
Department of Normal, Pathological and Clinical Physiology, Third Faculty of Medicine, Charles University, Ke Karlovu 4, 120 00 Prague 2 , Czech Republic.
Yamamotová
A
A
Tobiás
J
J
Rokyta
R
R
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001835:Body Weight; D002422:Causalgia / Q000503:physiopathology*; D004195:Disease Models, Animal; D005260:Female; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013126:Spinal Nerve Roots / Q000601:surgery