engleski

Tail pressure pain in Wistar rats: influence of gender and time of day

Background and purpose: The gender should be considered as a basic variable at all levels of biomedical and health related research. Thus, we tested the hypothesis whether gender and time of day affect tail pressure thresholds in Wistar rats. Materials and methods: 11 female and 11 male Wistar rats, in the age of 6 months were used. After two days of habituation period, tail pressure thresholds were determined twice a day (9.00-10.00 h and 15.00-16.00 h) in 3 consecutive days. Expressed in grams (g), the pain thresholds were measured by applying increasing force on the tail, until the tail was withdrawn as the result of pain. Data were analyzed using analysis of variance (ANOVA) and expressed as the mean &plusmn ; ; S.E.M. Results: The pain thresholds were significantly higher in male, as compared to female rats, when testing took place in the morning (days 1-3 ; F (5, 52) = 4.93 ; P<0.01). When testing took place in the afternoon, there was no difference in the pain threshold values between female and male rats (days 1-3 ; F (5, 52) = 2.19, not significant at P<0.05). Significant decrease in afternoon pain threshold values, as compared to morning values, was detected within male (days 1-3 ; F (5, 56) = 3.5 ; P<0.05), but not within female rats (days 1-3 ; F (5, 48) = 1.1 not significant at P<0.05). Conclusion: The results presented here indicate that both, gender and time of day within light phase of day cycle, affect tail pressure thresholds in Wistar rats.

Gender; Time of day; Tail pressure; Rat

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