条件反射性免疫抑制激活过程中下丘脑核团c-fos的表达

利用经典条件反射性免疫抑制的动物模型，以糖精水为条件刺激（CS），免疫抑制剂-环磷酰胺为非条件刺激 （UCS），观测两次CS-UCS结合训练后，再次条件刺激诱发条件反射性免疫抑制作用的动态改变，获得条件反射性免疫抑制和味觉厌恶性条件反射各自保持的情况，并在此基础上，采用c-fos免疫组化技术， 进一步观察再次条件刺激诱发条件反射性免疫抑制反应时大鼠下丘脑各核团内FOS蛋白的表达情况。结果表明，条件反射性免疫抑制作用在训练后第5天较强，第30天基本消失，而味觉厌恶性条件反射始终稳定保持到第30天。进一步研究显示出，下丘脑室旁核FOS蛋白表达在第5天非常密集，而第30天几乎没有表达，与细胞免疫功能改变在时程和趋势上具有一致性。通过FOS蛋白表达时程差异比较，提示下丘脑室旁核可能是CNS内介导CS诱导的免疫抑制效应的重要核团。

CONDITIONED IMMUNOSUPPRESSION AND THE EXPRESSION OF C-FOS IN THE HYPOTHALAMIC NUCLEI

Although there have been many reports that conditioned immunosuppression (CIS) can be achieved through behavioral conditioning techniques, little is known about the neural mechanisms of CIS. In this study, cyclophosphamide (CY) was used as an unconditioned stimulus (UCS) with saccharin as the conditioned stimulus (CS) in a conditioned taste aversion (CTA) paradigm. Both CTA and CIS as assessed by peripheral leukocyte and lymphocyte were examined by one re-exposure to CS at intervals of 5, 30 days after two trials of CS-UCS pairing. The effect of one re-exposure to CS on the expression of FOS-protein in the hypothalamus nucleus was also observed correspondingly. The results showed that CTA occurred on both day 5 and day 30 after conditioning but CIS occurred only on day 5 after conditioning. It was further found that some nuclei of hypothalamus, paraventricular nucleus (PVN) in particular, showed high expression of FOS-protein on the fifth day after one re-exposure to CS, but there was no or little expression of FOS-protein on the thirtieth day. By comparing the results of the fifth day with the thirtieth day,it is suggested that PVN of the hypothalamus is an important nuclear for modulating the response of CIS in the CNS.