Tail-Flick Latency and
Self-Mutilation Following Unilateral Deafferentation in Rats
N. KŘÍŽ, A. YAMAMOTOVÁ, J. TOBIÁŠ, R. ROKYTA
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
Summary
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
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