大鼠孤束核和最后区向中脑导水管周围灰质的直接投射

应用神经束路追踪技术对大鼠孤束核(NTS)和最后区(AP)向中脑导水管周围灰质(PAG)的直接投射进行了观察。结果表明: (1)中、尾段NTS的内侧亚核和连合亚核向PAG的投射最多,腹侧亚核与背侧亚核次之,中段多于尾段,内侧亚核多于连合亚核和腹侧亚核; (2)这些亚核向PAG的腹外侧区投射最多,向外侧区投射较少,向背侧区投射最少,向背外侧区无投射; (3 )AP区的吻侧部向尾段PAG的腹外侧区投射最多,向其他部位投射较少; (4)在PAG的吻尾方向上,这些投射从吻段到尾段逐渐增加; (5)NTS和AP向PAG的两侧均有投射,但以同侧投射占优势。上述结果为进一步揭示PAG与NTS和AP之间的功能关系奠定了形态学基础。

THE DIRECT PROJECTIONS FROM THE NUCLEUS TRACTUS SOLITARIUS AND AREA POSTREMA TO THE PERIAQUEDUCTAL GRAY IN THE RAT

The direct projections from the nucleus tractus solitarius (NTS) and area postrema (AP) to the periaqueductal gray (PAG) were investigated in the rat by using tract-tracing techniques. The results were as follows: (1) Most of the projections to the PAG were from the medial subnuclei and commissural subnuclei of NTS at the level of caudal and middle segments. The projections from the level of middle segment were more than those at the level of caudal segment and the projections from the medial subnuclei were more than those from the commissural subnuclei of NTS. (2) In PAG, most of the afferent projections from the NTS were found to terminate in the ventrolateral region, less in the lateral region and the least in the dorsal region. No afferent projections were observed in the dorsolateral region. (3) Rostral part of the AP had most projection fibers to the ventrolateral region of the PAG, only a few projection fibers were observed in other regions of the PAG. (4) At the caudal-rostral plane of the PAG, the projections gradually increase from the rostral part to the caudal part. (5) The projections from the NTS and AP to the PAG were bilateral, however it had an ipsilateral dominance. The results provided morphologic basis for further investigation on the correlation of function between the PAG and NTS.