Romero M T, Bodnar R J
Physiol Behav. 1986;37(6):893-7.
Female rats display lower shock thresholds and less morphine analgesia than male rats, differences which are sensitive to gonadal manipulations. Baseline pain thresholds and morphine analgesia also vary across the estrous cycle of female rats. The first experiment demonstrated that 'nonopioid' continuous cold-water swim (CCWS: 2 degrees C for 3.5 min) analgesia and 'opioid' intermittent cold-water swim (ICWS: 2 degrees C, 18 10-sec swims and 10-sec rests over 3 min) analgesia are subject to gender-specific effects. The magnitudes of CCWS and ICWS analgesia were significantly lower in female rats as compared to either age-matched or weight-matched male rats. The jump test displayed a more consistent pattern than the tail-flick test. The second experiment failed to show differences in the magnitude of CCWS analgesia across the female estrous cycle. These data demonstrate that both opioid (ICWS) and nonopioid (CCWS) forms of stress-induced analgesia are sensitive to gender differences, and suggest that male gonadal hormones may enhance analgesic responsivity.
雌性大鼠比雄性大鼠表现出更低的电击阈值和更少的吗啡镇痛效果，这些差异对性腺操作敏感。雌性大鼠的基线疼痛阈值和吗啡镇痛效果在发情周期中也有所不同。第一个实验表明，“非阿片类”持续冷水游泳（CCWS：2摄氏度，持续3.5分钟）镇痛和“阿片类”间歇性冷水游泳（ICWS：2摄氏度，3分钟内进行18次10秒游泳和10秒休息）镇痛存在性别特异性效应。与年龄匹配或体重匹配的雄性大鼠相比，雌性大鼠的CCWS和ICWS镇痛幅度显著更低。跳跃试验比甩尾试验显示出更一致的模式。第二个实验未能显示雌性发情周期中CCWS镇痛幅度的差异。这些数据表明，应激诱导的镇痛的阿片类（ICWS）和非阿片类（CCWS）形式都对性别差异敏感，并表明雄性性腺激素可能增强镇痛反应性。
