Figure 4: (a) Baseline tail flick latency in spontaneously cycling female Wistar rats in proestrus (Pro) and late dioestrus (LD) and in rats undergoing progesterone treatment (HP) or withdrawal from an exogenous progesterone dosing regime (PWD). Data show mean values of three readings taken at 5-minute intervals. All values . Pro: , LD: , HP: , PWD: . (b) Change in tail flick latency (TFL) following 5-minute exposure to nonnoxious vibration stress in normally cycling and progesterone-withdrawn female Wistar rats. Data represent mean values obtained during 10 minutes immediately poststress as a percentage of the mean baseline level measured during 10 minutes prior to the stress. A control group comprising rats in proestrus and late dieostrus received no vibration stress. All values ; no stress (control): , Pro: , LD: , HP: , PWD: . , post hoc Dunnett’s test in comparison to control group after significant ( ) one-way ANOVA.