性腺激素影响雄性和雌性大鼠的饮酒行为,但不影响线索加育亨宾诱导的觅酒行为。
Gonadal hormones affect alcohol drinking, but not cue+yohimbine-induced alcohol seeking, in male and female rats.
机构信息
Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15219, United States.
Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15219, United States.
出版信息
Physiol Behav. 2019 May 1;203:70-80. doi: 10.1016/j.physbeh.2017.10.025. Epub 2017 Oct 26.
Alcohol use disorder (AUD) is a chronic, relapsing disease characterized by maladaptive patterns of alcohol drinking and seeking. Though sex differences exist in the etiology of AUD, much remains to be elucidated concerning the mechanisms underlying sex-related vulnerability to developing excessive alcohol-motivated behavior. While a large body of evidence points to an important role of circulating gonadal hormones in mediating cocaine reinforcement, findings are less consistent with respect to ethanol. Critically, the effects of gonadal hormones on the reinstatement of ethanol seeking, a model of "craving"-like behavior that reveals pronounced sex differences, has not yet been examined. Thus, the goal of the present experiment was to directly compare manipulations of gonadal hormones in male and female rats on ethanol-motivated behavior. Rats received sham or gonadectomy surgery with or without hormone replacement prior to and throughout three weeks of operant ethanol self-administration to determine the effects of chronically high or low gonadal hormone levels on ethanol drinking. Hormone treatment ceased during extinction training, and the effects of an acute injection of either testosterone (in males) or estradiol (in females) on cue+yohimbine-induced reinstatement of ethanol seeking was determined. Separate groups of gonadally-intact female rats went through similar training, but the effects of either the antiestrogen, fulvestrant, the selective estrogen receptor modulator, clomiphene, or the estrogen receptor β antagonist, PHTPP, on the reinstatement of ethanol seeking were determined. Chronic estradiol replacement produced significant increases in ethanol drinking in female rats, while chronic testosterone significantly decreased ethanol drinking in male rats. Gonadectomy alone only produced modest shifts in drinking towards the opposite-sex pattern, and did not eliminate the robust sex differences that persisted regardless of hormone manipulations. Neither prior chronic nor acute hormone manipulations altered cue+yohimbine-induced reinstatement of ethanol seeking, though blockade of estrogen receptors tended to reduce reinstatement in gonadally-intact females. Overall, our findings indicate that gonadal hormones at least partially mediate, but do not totally account for the sex differences evident in ethanol self-administration, and circulating gonadal hormones have little effect on the reinstatement of ethanol seeking. These results provide a foundation for future studies examining the neuronal mechanisms underlying sex differences in ethanol drinking and seeking.
酒精使用障碍(AUD)是一种慢性、复发性疾病,其特征是饮酒和寻求酒精的适应不良模式。尽管 AUD 的病因存在性别差异,但对于导致过度酒精动机行为的性别相关易感性的机制仍有很多需要阐明。虽然大量证据表明循环性腺激素在介导可卡因强化方面起着重要作用,但关于乙醇的发现则不太一致。至关重要的是,性腺激素对乙醇寻求的复燃的影响,即一种表现出明显性别差异的“渴望”样行为模型,尚未得到研究。因此,本实验的目的是直接比较雄性和雌性大鼠中性腺激素的操作对乙醇动机行为的影响。在进行三周的操作性乙醇自我给药之前和期间,大鼠接受假手术或性腺切除术,同时或不进行激素替代治疗,以确定慢性高或低性腺激素水平对乙醇摄入的影响。在消退训练期间停止激素治疗,并确定急性注射睾丸激素(雄性)或雌二醇(雌性)对线索+育亨宾诱导的乙醇寻求复燃的影响。一组单独的性腺完整雌性大鼠接受了类似的训练,但确定了抗雌激素氟维司群、选择性雌激素受体调节剂氯米芬或雌激素受体 β 拮抗剂 PHTPP 对乙醇寻求复燃的影响。慢性雌二醇替代会导致雌性大鼠的乙醇摄入量显著增加,而慢性睾丸激素会显著降低雄性大鼠的乙醇摄入量。单独的性腺切除术仅导致向相反性别模式的适度饮酒转变,并且不会消除无论激素操作如何都持续存在的强烈性别差异。无论是之前的慢性还是急性激素操作都没有改变线索+育亨宾诱导的乙醇寻求复燃,尽管阻断雌激素受体往往会减少性腺完整的雌性动物的复燃。总的来说,我们的发现表明,性腺激素至少部分介导,但不能完全解释乙醇自我给药中明显的性别差异,并且循环性腺激素对乙醇寻求的复燃影响很小。这些结果为未来研究提供了基础,以研究性别差异饮酒和寻求的神经元机制。