Llaneza Danielle C, Frye Cheryl A
Dept. of Psychology, The University at Albany-SUNY, Albany, NY 12222, USA.
Pharmacol Biochem Behav. 2009 Sep;93(3):337-42. doi: 10.1016/j.pbb.2009.05.003. Epub 2009 May 14.
Steroid hormones, progesterone and estradiol, may influence approach and/or anxiety behavior. Female rats in behavioral estrous, have elevated levels of these steroid hormones and demonstrate more approach and less anxiety behavior than do diestrous rats. Ovariectomy obviates these cyclic variations and systemic progesterone and/or estrogen replacement can enhance approach and anti-anxiety behavior. However, the role of progesterone and/or estrogen in mediating impulsive, avoidant and/or fear behaviors requires further investigation. We hypothesized that if progesterone and/or estrogen influences impulsivity and/or fear then rats in behavioral estrous would demonstrate less impulsive behavior in a burying task and freezing behavior in a conditioned fear task than will diestrous rats. Ovariectomized rats administered progesterone and/or estrogen would show less impulsive burying and freezing behaviors than will vehicle-administered rats. Experiment 1: Naturally cycling rats were tested in marble burying or conditioned fear when they were in behavioral estrous or diestrous. Experiment 2: Ovariectomized rats were administered progesterone, estrogen or vehicle, then tested in marble burying or conditioned fear. Results of Experiment 1 show rats in behavioral estrous demonstrate less impulsive burying and less freezing behavior than diestrous rats. Results of Experiment 2 show administration of progesterone or both estrogen and progesterone decreases impulsive burying and each decrease freezing behavior compared to vehicle. Thus, progesterone and/or estrogen may mediate impulsive and/or avoidant behavior.
类固醇激素、孕酮和雌二醇可能会影响趋近行为和/或焦虑行为。处于行为发情期的雌性大鼠，这些类固醇激素水平升高，与处于动情间期的大鼠相比，表现出更多的趋近行为和更少的焦虑行为。卵巢切除术消除了这些周期性变化，全身给予孕酮和/或雌激素可以增强趋近行为和抗焦虑行为。然而，孕酮和/或雌激素在介导冲动、回避和/或恐惧行为中的作用需要进一步研究。我们假设，如果孕酮和/或雌激素影响冲动性和/或恐惧，那么处于行为发情期的大鼠在埋珠任务中的冲动行为和在条件性恐惧任务中的僵住行为会比处于动情间期的大鼠少。给予孕酮和/或雌激素的卵巢切除大鼠与给予赋形剂的大鼠相比，冲动性埋珠和僵住行为会更少。实验1：对处于行为发情期或动情间期的自然发情周期大鼠进行埋珠或条件性恐惧测试。实验2：给卵巢切除大鼠给予孕酮、雌激素或赋形剂，然后进行埋珠或条件性恐惧测试。实验1的结果表明，处于行为发情期的大鼠比处于动情间期的大鼠表现出更少的冲动性埋珠和更少的僵住行为。实验2的结果表明，与赋形剂相比，给予孕酮或同时给予雌激素和孕酮会减少冲动性埋珠，且每种处理都会减少僵住行为。因此，孕酮和/或雌激素可能介导冲动和/或回避行为。
