Relationship among sexual differences of susceptibility to motion sickness, AVP levels of plasma and pituitary and V1b receptor expression of pituitary in rats / 中国应用生理学杂志

ABSTRACT

<p><b>AIM</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>