大鼠视交叉上核与室旁核的联系──病毒跨神经元顺行追踪研究

THE CONNECTION BETWEEN THE SUPRACHIASMATIC NUCLEUS AND THE PARAVENTRICULAR NUCLEUS IN THE RAT──STUDY USING ANTEROGRADE OF VIRUS TRANSNEURONAL TRACING

本实验采用假狂犬病毒（猪疱疹病毒）作为跨神经元追踪示踪物，对下丘脑视交叉上核与下丘脑室旁核的联系进行了研究．实验大鼠于摘除双侧颈上交感神经节后，向单侧眼球内注入假狂犬病毒，术后动物分别存活48、56、72及96h．结果显示：56h组仅在视交叉上核内有极少数的细胞被病毒感染；72h组机交叉上核内被病毒标记的细胞增多，定劳核内也出现了被病毒感染的神经元，主要集中在背内侧帽区；96h组在室旁核内被病毒感染的神经元增加，除背内侧帽区外，其它亚孩也出现了被病毒感染的神经元；各实验组的亚室旁带未见有被病毒标记的神经元．以上表明视交叉上核的传出纤维直接投射到室旁核，两核团神经无间可能存在有直接的突触联系．

It is necessary to study the connection of the suprachiasmatic nucleus (SCN) with the rest parts of the brain, since SCN is a dominate pacemaker involved in the generation of circadian rhythm in mamma1s. The paraventricular nucleus (PVN) mainly regulates many of the autonomic and neuroendocrine circadia rhythm, which are controled by SCN. However, the connection between the SCN and PVN is not clear. The present study applied pseudorabies virus(PRV) as an anterograde transsynaptic tracer. Forty adult maIe Sprague-Dawley(SD) rats were subjected to a supracervical sympathetic ganglionectomy to eIiminate viral transport via the sympathetic innervation before uniocular injection of 3μl PRV(Bartha strain,5×108PFU/ml). The rats were killed at 48,56.72 and 96 hours after operation respectivelly. The prefix rinse(100 units ofheparin per 100 ml isotonic saline) and fixative (4. 0% para formaldehyde, 0. 25% g1utaraldebyde, 1. 37% DL-lysine and 0.214 % sodium-m-periodate in 0. 1 mol/L PB pH 7. 4) were used. The brain was removed from the skull and stored in the fix ative for 1 h, then transferred into 20% sucrose in 0. 1 mol/L PB(pH 7. 4) for 24 hours. Neurons labeIled with PRV were shown by immunofluorescent and immunohistochernical ABC methods. Results: (1)No neuron was infected by PRV in the SCN and the PVN at 48 hours. (2)A few neurons only in the SCN were infected by PRV at 56 hours. (3)Numerous neurons labelled by PRV presented in SCN, but in the PVN the labelling neurons were found predominatly in the dorsomedial cap at72 hours. (4)With the survival time, the number of neurons infected by PRV were increasing, PRV labelling neurons occutred in the medial patvocellular part and lateral magnocellular part of the PVN besides in the dorsomedial cap at 96 hours.However, no neuron labelled by PRV was found in the subparaventricular zone. This study indicates that there is a directprojection frorn SCN to the PVN and PRV is a useful transneuronal tracer.