Mora S, Dussaubat N, Díaz-Véliz G
Instituto de Ciencias Biomédicas, Programa de Farmacología Molecular y Clínica, Facultad de Medicina, Universidad de Chile, Santiago.
Pharmacol Biochem Behav. 1998 Nov;61(3):221-8. doi: 10.1016/s0091-3057(98)00082-3.
Several studies have demonstrated that the peptide LHRH can modify behavior in the male rat. Peripheral and intracerebral infusions of LHRH impair the acquisition of conditioned avoidance responses (CARs) and increase some spontaneous motor behaviors, such as head shaking and grooming. The present study was undertaken to detect the effects of LHRH on the acquisition of CARs and spontaneous motility in normally cycling and ovariectomized (OVX) Sprague-Dawley female rats. Normally cycling females were separated in four groups, according to the stage of the estrous cycle. Ovariectomized female rats were pretreated, 48 h before the experiment, with estradiol benzoate (10 microg/kg) or corn oil. LHRH (6.25, 25, or 50 microg/kg) was subcutaneously injected and the behavioral tests began 1 h after. Low doses of LHRH stimulated the acquisition of CARs during proestrus, estrus, and metestrus, whereas higher doses impaired conditioning in all the four stages of the cycle. High doses of LHRH impaired acquisition in OVX rats treated with oil and potentiated the depressant effects of EB on this behavior. The effects of LHRH on spontaneous motor activity were either stimulatory or inhibitory, according to the hormonal status and the dose administered. High doses of LHRH decreased motor responses in the diestrous rat. All the doses of LHRH increased the number of headshakes during proestrus, estrus, and metestrus, while the other motor responses were scarcely or not affected by LHRH in these stages. In OVX rats LHRH increased rearing, head shaking, and grooming behavior. These results support a role of LHRH in the modulation of conditioned and spontaneous behavior. They could provide an explanation to the behavioral changes observed across the estrous cycle and those observed after EB priming in OVX rats.
多项研究表明，肽促性腺激素释放激素（LHRH）可改变雄性大鼠的行为。外周和脑内注射LHRH会损害条件性回避反应（CARs）的习得，并增加一些自发运动行为，如摇头和梳理毛发。本研究旨在检测LHRH对正常发情周期和去卵巢（OVX）的斯普拉格-道利雌性大鼠CARs习得和自发运动能力的影响。正常发情周期的雌性大鼠根据发情周期阶段分为四组。去卵巢雌性大鼠在实验前48小时用苯甲酸雌二醇（10微克/千克）或玉米油进行预处理。皮下注射LHRH（6.25、25或50微克/千克），1小时后开始行为测试。低剂量的LHRH在发情前期、发情期和发情后期刺激CARs的习得，而高剂量则在周期的所有四个阶段损害条件反射。高剂量的LHRH损害用玉米油处理的OVX大鼠的习得，并增强雌二醇对这种行为的抑制作用。根据激素状态和给药剂量，LHRH对自发运动活动的影响要么是刺激性的，要么是抑制性的。高剂量的LHRH降低了动情间期大鼠的运动反应。所有剂量的LHRH在发情前期、发情期和发情后期增加了摇头次数，而在这些阶段其他运动反应几乎没有或不受LHRH影响。在OVX大鼠中，LHRH增加了竖毛、摇头和梳理毛发行为。这些结果支持LHRH在调节条件性行为和自发行为中的作用。它们可以解释在整个发情周期观察到的行为变化以及在OVX大鼠中用雌二醇预处理后观察到的行为变化。
