Farook J M, McLachlan C S, Zhu Y Z, Lee L, Moochhala S M, Wong P T-H
Department of Pharmacology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
Neurosci Lett. 2004 Jan 30;355(3):205-8. doi: 10.1016/j.neulet.2003.11.010.
Our previous studies (NeuroReport 12 (2001) 2717) showed that PVG hooded and not Sprague-Dawley (SD) rats exhibit remarkable freezing behavior on exposure to a cat in the cat freezing test apparatus. In the present study, we further examined the differences between these two strains of rats in response to repeated daily exposure to a cat in the cat freezing test apparatus. Freezing behavior habituation was observed in both PVG hooded (days 5-7) and SD rats (days 3-7). A selective CCK(2) agonist (BC264, 0.3 microg/kg, i.p.) on day 8 reversed habituated freezing behavior and locomotor activity in PVG hooded rats, but not in SD rats. These results suggest that CCK2 receptors mediate habituation to an anxiety-inducing stimulus in PVG hooded rats and further suggest that differential expression of these CCK2 receptors underlies this strain difference.
我们之前的研究（《神经报告》12 (2001) 2717）表明，在猫冷冻试验装置中暴露于猫时，PVG 有帽大鼠而非斯普拉格-道利（SD）大鼠表现出显著的僵住行为。在本研究中，我们进一步研究了这两种品系的大鼠在猫冷冻试验装置中每天重复暴露于猫时的反应差异。在 PVG 有帽大鼠（第 5 - 7 天）和 SD 大鼠（第 3 - 7 天）中均观察到僵住行为的习惯化。第 8 天腹腔注射选择性 CCK(2) 激动剂（BC264，0.3 μg/kg）可逆转 PVG 有帽大鼠习惯化的僵住行为和运动活动，但对 SD 大鼠无效。这些结果表明，CCK2 受体介导了 PVG 有帽大鼠对焦虑诱导刺激的习惯化，进一步表明这些 CCK2 受体的差异表达是该品系差异的基础。
