central effect of xylazine and yohimbin on pain sensitivity of rat during estrous cycle in formalin test

sex hormone is supposed to modify pain sensitivity. the aim of the present study was to investigat, the role of 2 adrenergic receptors in nociception using formalin test. formalin test was performed by subcutaneous injection of 50 ml formalin (%2.5) solution into hind paw. animals were divided into 4 groups as control group (intact animal), sham group (received 2µl of artificial csf by icv route), agonist group (received 2µl of xylazine 5 and 10 mg / rat by icv route) and antagonist group (received 2µl of yohimbin 5 and 10 mg /rat by icv route). data were analyzed by two way anova and post- hoc test of tukey's test. data showed that xylazine significantly decreased (p