THE INFLUENCE OF COLONIC TEMPERATURE-CHANGES IN ANESTHETIZED RATS ON TAIL SKIN TEMPERATURES AND REPEATED TESTING OF TAIL-FLICK LATENCIES

Tail-flick (TF) response latencies were measured in pentobarbitone-ana esthetized rats and variations with time, body and tail temperatures a nd 5 tail stimuli positions analysed with a mixed model analysis of va riance. Variation with time was not significant. Highly significant di fferences (P < 0.001) were found between tail-flick latencies (TFLs) f or tail temperatures and stimulus position. The most proximal tail pos ition showed significantly different relationships for TFL with time a nd body temperature from other positions. The method described-allows multiple TFLs to be measured in 1 animal with the potential of reducin g the total number of animals in an experiment. Tail stimuli positions from proximal to distal sites showed a variation in response from 4.3 sec (95% CI: 4.2, 4.4) to 6.7 sec (95% CI: 6.6, 6.9). Rat tail stimul us position should therefore be standardised to allow reproducible mea sures of TFL and body temperature maintained within normal limits. TFL s were found to be abnormal at body temperatures above 39 degrees C.