Molina-Hernández M, Contreras C M, Téllez-Alcántara P
Laboratorio de Conducta, Instituto de Investigaciones Psicológicas, Universidad Veracruzana, Veracruz, México.
Neuropsychobiology. 2001 Jan;43(1):29-33. doi: 10.1159/000054862.
Both anxiety-like behavior and the response to anxiolytic drugs vary according to the estrus cycle in the rat. Consequently, anxiety-like behavior and the sensitivity to anxiolytic drugs may be related to hormone level fluctuations occurring during the estrus cycle. In male rats tested in a conflict-operant paradigm, anxiolytic drugs increase immediate punished responding. However, it is unknown whether estrus phases impinge on the immediate punished responses in a conflict-operant paradigm. Therefore, in this study female rats were trained in a conflict-operant paradigm; after training all animals received vehicle or diazepam. Then the number of immediate punished reinforcers was evaluated during the estrus cycle. Results showed that vehicle-treated rats evaluated during late proestrus and estrus obtained a higher (p < 0.05) number of immediate punished reinforcers than rats evaluated during metestrus and diestrus. A low dose of diazepam (1.3 mg/kg; i.p) significantly increased (p < 0.05) the immediate punished responses only in late proestrus and estrus. The highest dose of diazepam tested (2.0 mg/kg; i.p.) significantly increased (p < 0.05) the immediate punished reinforcement in any estrus phase. These results suggest that a lower level of anxiety-like and an increased sensitivity to an anxiolytic drug occurred only in late proestrus and estrus in rats tested in a conflict-operant paradigm.
在大鼠中，焦虑样行为以及对抗焦虑药物的反应会根据发情周期而有所不同。因此，焦虑样行为和对抗焦虑药物的敏感性可能与发情周期中发生的激素水平波动有关。在采用冲突操作性范式进行测试的雄性大鼠中，抗焦虑药物会增加即时受罚反应。然而，发情阶段是否会影响冲突操作性范式中的即时受罚反应尚不清楚。因此，在本研究中，对雌性大鼠进行了冲突操作性范式训练；训练后，所有动物接受溶剂或地西泮。然后在发情周期中评估即时受罚强化物的数量。结果显示，在发情后期和发情期接受评估的溶剂处理大鼠比在动情后期和动情间期接受评估的大鼠获得了更高（p<0.05）数量的即时受罚强化物。低剂量地西泮（1.3mg/kg；腹腔注射）仅在发情后期和发情期显著增加（p<0.05）即时受罚反应。所测试的最高剂量地西泮（2.0mg/kg；腹腔注射）在任何发情阶段均显著增加（p<0.05）即时受罚强化。这些结果表明，在采用冲突操作性范式进行测试的大鼠中，仅在发情后期和发情期出现较低水平的焦虑样行为以及对抗焦虑药物的敏感性增加。
