【作者】 王贤峰；

【导师】 张洪海；

【作者基本信息】 曲阜师范大学 ， 动物学， 2006， 硕士

【摘要】 本研究以分布于鲁中南山地丘陵的黑线姬鼠（Apodemus agrarius）为研究对象,利用黄鼬（Mustelia siberica）肛腺模拟田鼠天敌的气味源,系统研究了雄性黑线姬鼠在长期黄鼬气味影响下社会冲突的改变。主要研究结论如下: 1 利用新型荧光试剂1,2-苯并-3,4-二氢咔唑-9-乙基肼基甲酸酯（BCEC）作柱前衍生化试剂,在Hypersil BDS C18（4.6×200mm,5μm）色谱柱上,采用梯度洗脱对皮质醇、皮质酮、睾酮、孕酮四种类固醇荧光衍生物进行了优化分离。65℃下在乙腈溶剂中以三氯乙酸作催化剂,衍生反应2小时后获得稳定的荧光产物。激发和发射波长分别为λ_ex=333nm,λ_em=390nm。采用大气压化学电离源（APCI）正离子模式,实现了黑线姬鼠粪便中四种类固醇化合物的定性及定量测定。线性回归系数均在0.9999以上,检测限为47.3—71.2fmol。 2 胁迫之后攻击行为频次的升高认为是由肾上腺激素调节的一种积极适应策略。雄性黑线姬鼠在第1天的攻击行为频次比对照组显著升高（Z=2.21,P=0.028）。第1天实验组攻击行为比对照组显著升高（Z=2.21,P=0.028）,而在第21天和第28天实验组攻击行为显著下降（day21,Z=2.26,P=0.02;day28,Z=2.1,P=0.037）。说明,短期（6小时）气味处理能促进雄性黑线姬鼠攻击行为的发生,而长期气味影响下显著抑制雄性黑线姬鼠攻击行为的发生。 3 实验组在第21天和第28天攻击潜伏期显著升高说明长期暴露在黄鼬气味下,雄性黑线姬鼠攻击潜伏期显著上升;对攻击行为与攻击潜伏期的相关线性分析结果表明,攻击强度随攻击潜伏期的增加而显著降低。说明在社会冲突中攻击行为发生的越早攻击的强度越大。 4 黄鼬气味对雄性黑线姬鼠的脾脏、肾上腺、生殖器官及精子数量没有影响。实验结果支持天敌气味对鼠类的生殖生理器官影响不显著。 5 雄性黑线姬鼠在应对不同的胁迫处理中内分泌反应调节机制不同。28天内5次社会冲突后对照组中胜利鼠和失败鼠皮质酮水平没有显著变化。说更多还原

【Abstract】 Predation is one of the strongest selective pressures. Mustelid odors have been shown to suppress breeding in voles. The mechanism behind the suppression is unknown. Social conflict is necessary for successful reproduction, and for the defense of resources. Engaging in social conflict is necessary for the formation of social structure. Social behavior interacts with the hormones and immune function in a complex bidirectional fashion. Hormones can act directly on the neural circuits that regulate specific behaviors to change the functioning of those circuits and thereby change the expression of behavior;Social encounters can regulate the levels of various hormones and influence immune function of the individuals.Measuring steroid hormone metabolites in fecal samples has become a widely appreciated technique, because it has been proved to be a powerful noninvasive tool that provides important information about an animal’s endocrine status (adrenocortical activity and reproductive status). Measurement of these hormones in fecal extracts by high-performance liquid chromatography (HPLC) was validated using chemical derivatization, mass spectrometry.This study investigated: 1) to develop a method for assessment of fecal glucocorticoids (specifically cortisol and corticosterone) as a measure of stress in rodents, specifically striped field mice Apodemus agrarins, 2) the effect of social conflict on the behavior, physiology and endocrine response of male striped field mice, 3) examined the effects of predator odor on the incidence of aggressive behaviors between male striped field mice relative to unstressed controls. Themain results of this are as follow.1. A simple and sensitive method for the determination of steroid compounds extracted from mice feces using l,2-benzo-3, 4-dihydrocarbazole-9- ethyl-carbonylhydazine (BCEC) as pre-column derivatization reagent by high-performance liquid chromatography in combination with a gradient elution with fluorescence detection and mass spectrometric identification has been developed. Studies on derivatization conditions indicate that steroid compounds react with BCEC at 65 °C within a two-hour period in the presence of trichloroacetic acid (TCA) catalyst with acetonitrile as reaction co-solvent to give the corresponding sensitive fluorescence derivatives. The fluorescence excitation and emission wavelengths are set at Xex 333 and Xem390nm, respectively. The identification of steroid derivatives is performed under APCI source in positive-ion mode. Correlation coefficients for steroid derivatives are >0.9999, and detection limits (at signal-to-noise ratio of 3:1). are 47.3—71.2 fmol. The established method is sensitive and reproducible for the determination of steroid compounds from real samples with satisfactory results.2. Our data indicate that there are effects of both short-term and long-term predator odor stress on the incidence of aggressive conflicts, an effect that is correlated with the HPA axis response. Short-term stress exposure significantly elevated the incidence of aggression among stress mice relative to unstressed controls (Dayl, Z=2.21, P=0.028).Alternatively, long-term stress significantly lowered aggression among stress (day21, Z=2.26, P=0.02;day28, Z=2.1, P=0.037).3. Long-term predator odor stress significantly lowered attack latency among stress mice, and there was a significant relationship between attack latency and total aggressive behavior. Males that attacked earlier displayed more aggressive behavior overall.4. Long-term predator odor stress did not significantly alter the Liver, Spleen, Adrenal, Testis, Epididymis and Sperm count. As in other rodent species,predator odor did not affect the reproductive organs and adrenal size in adult mice.5. The male mice activate the HPA axis responses to cope with different stressful social environment. Among control mice, corticosterone levels of the winner and loser did not significantly alter. While under repeated predator odor, corticosterone levels of the winner and loser were significantly higher than baseline. Predator odor is more stressful than social contact for male mice.Presumably, the positive social interaction suppresses the HPA axis and decreases basal cortisol concentrations to eliminate the predator odor effect. Among control mice, cortisol levels of the winner were higher than that of the loser.Winning fights elevates testosterone levels in male mice and enhance future chance to win fights among control. Testosterone levels of the winner increased with prior winning experience, while predator odor can enhance the testosterone secretion and long-term exposure can inhibit secretion.更多还原