大鼠运动病敏感性性别差异与血浆和垂体中AVP水平及垂体V1b受体表达水平的关系

目的：观察不同性别大鼠旋转前后不同时间点血浆和垂体精氨酸加压素（AVP）的含量以及垂体AvP—V1b受体阳性神经元数目和受体表达量,探讨AVP与运动病性别差异间的联系,为进一步认识运动病的发病机制提供实验依据。方法：采用条件性厌食症作为运动病模型。98只SD大鼠,雌雄各半,分别用放射免疫分析法、免疫组化及Western—blot法测定血浆、垂体AVP含量和垂体V1b受体表达水平。结果：旋转刺激后雌性大鼠糖精水（0．15％）饮用量的减少程度高于雄性大鼠。雌性大鼠血浆AVP含量在基础状态下高于雄性大鼠,旋转刺激后下降,而雄性大鼠无显著性变化。雌性大鼠垂体AVP含量在基础状态下也高于雄性大鼠,旋转刺激后8h下降。24h降低有显著性;雄性大鼠旋转后8h垂体AVP含量较旋转前明显下降,但降幅不及雌性大鼠,旋转后24h已近恢复。与应激反应密切相关的垂体V1b受体表达为阳性的神经元数目及V1b受体表达水平,在基础状态下,雌性大鼠显著高于雄性;旋转刺激后,雌性大鼠V1b受体表达为阳性的神经元数目和表达水平均明显降低,而雄性大鼠则无显著性改变。结论：运动病诱发刺激后,雌雄性大鼠血浆和垂体中AVP含量及垂体V1b受体表达均有差异,提示AVP的内分泌状态与运动病敏感性性别差异可能有某种关联。

Relationship among sexual differences of susceptibility to motion sickness, AVP levels of plasma and pituitary and V1b receptor expression of pituitary in rats

Aim: To investigate the relationship among sexual differences of motion sickness(MS),AVP levels of plasma and pituitary and the expression of pituitary V1b receptors for further understanding of the MS mechanisms.Methods: The conditioned taste aversion(CTA) of 0.15% saccharin sodium solution(SSS) was served as MS model.98(49 male and 49 female) rats were used in this experiment,50 for the detection of the AVP level in plasma and pituitary with radioimmunoassay(RIA),12 for the observation of the number of V1b receptor-positive neurons in the pituitary with the fluorescence immunohistochemistry method,the rest for the evaluation of the expression of V1b receptor in the pituitary by Western blot.Results: With regard to male rats,decrease of the drinking volume of 0.15% SSS was greater in female rats after rotatory stimulation.The plasma AVP concentration of female rats was significantly higher than that of males under normal conditions,but reduced significantly after rotatory stimulation.However,no significant change was found in male rats.In addition,the pituitary AVP level of the female rats was significantly higher than that of the male rats under normal conditions,but decreased at 8 h and significantly at 24 h after rotation.Similarly,the pituitary AVP level of male rats also decreased significantly at 8 h after rotation,but this decrease was not comparable to that of the females.At 24 h after rotation the pituitary AVP level almost recovered in male rats.In the pituitary,which was related to the stress response,the V1b receptor-positive neurons and the expression level of V1b receptor in female rats were significantly higher than those of the male rats,but they decreased significantly after rotation, while no apparent change was detected in the male rats.Conclusion: The changes of plasma and pituitary AVP and V1b receptor level of the pituitary after rotatory stimulation are different between male and female rats and the AVP secretion of the pituitary may be involved in the sexual difference in susceptibility to motion sickness.