Tail-flick test. I: Impact of a suprathreshold exposure to radiant heat on pain reactivity in rats.
Radiant heat applied to the tail elicits a vigorous tail-flick response in rats. This tail-flick reflex is frequently used to measure pain reactivity. Prior research has shown that a suprathreshold exposure to the radiant heat used to elicit this reflex causes a reduction in tail-flick latencies in pentobarbital anesthetized rats. Experiment 1 replicated this observation and showed that the effect is not due to a change in tail temperature. Experiment 2 showed that reduced latencies (hyperalgesia) are not observed if the spinal cord is transected prior to testing. Experiment 3 revealed that pentobarbital anesthesia is required to observe thermal-induced hyperalgesia, for this effect is not observed in awake subjects. Experiments 4 and 5 extended this observation by showing that awake rats also fail to exhibit hyperalgesia if others measures of pain reactivity are employed (shock-induced vocalization and motor reactivity). Implications of the results are discussed.
Kallina
C F
CF
Department of Psychology, Texas A & M University, College Station 77843, USA.
Grau
J W
JW
D000818:Animals; D008297:Male; D009619:Nociceptors / Q000187:drug effects / Q000502:physiology*; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology*; D010424:Pentobarbital / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012018:Reflex / Q000187:drug effects / Q000502:physiology*; D013116:Spinal Cord / Q000187:drug effects / Q000502:physiology; D013623:Tail / Q000294:innervation; D013697:Thermosensing / Q000187:drug effects / Q000502:physiology*
D010424:Pentobarbital