Physiol. Res. 55: 213-220, 2006

Tail-Flick Latency and Self-Mutilation Following Unilateral Deafferentation in Rats


Department of Normal, Pathological and Clinical Physiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic

Received March 21, 2005
Accepted April 25, 2005
On-line available May 24, 2005

Unilateral deafferentation induced by transection of the C4-C8 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.

Key words
Deafferentation • Nociception • Rats • Self-mutilation • Tail-flick

© 2006 by the Institute of Physiology, Czech Academy of Sciences