RESUMEN
Introduction: It is well recognized that gender and race differences play a role in pain sensitivity, pain perception, response to analgesic drug and prevalence of certain chronic pain disorders. In this study investigated gender and strainrelated differences in the effect of food deprivation on formalin induced nociceptive behaviors in rats
Methods: This study was done in Qazvin University of Medical Sciences 8 groups of rats [220-300gr]. Groups 1 and 2: Effect formalin-induced nociceptive behaviours in male and female Sprague-Dawley rats. Groups 3 and 4: Effect formalin-induced nociceptive behaviours in male and female Wistar rats. Groups 5 and 6: Effect of food deprivation on formalin-induced nociceptive behaviours in male and female Sprague-Dawley rats. Groups 7 and 8: Effect of food deprivation on formalin-induced nociceptive behaviours in male and female Wistar rats. Food was withdrawn 48 h [short-term food deprivation] prior to performing the formalin test, but water continued to be available ad libitum. The formalin [50 microL, 2%] was injected into hind plantar paw. Immediately after the formalin injection, pain behaviors recorded for 90 minutes
Results: There is significant difference between male and female control Sprague-Dawley rats during phase 2B. Although interphase in male rats is more than female ones, but the phase 2B in female rats is more than male ones and phase 2 finished with delay in Sprague-Dawley race. There are no significant differences between male and female control Wistar rats during formalin test. Following 48-h food deprivation, male and femalerats exhibited enhanced nociceptive behaviors in response to formalin injection during phase 1, the interphase, phase 2. In contrast, 48 h food deprivation had significant effect on formalinevoked nociceptive behaviors in phase 2B for male Wistar and in interphase and phase 2B for female rats
Conclusion: The present study demonstrates the existence of gender and strain-related differences in rats in the development and maintenance of inflammatory hyperalgesia. Also, these differences observed following food deprivation