胃肠道伤害性刺激引起大鼠孤束核与中脑导水管周围灰质神经元表达FOS

RECIPROCAL PROJECTION NEURONS BETWEEN THE MIDBRAIN PERIAQUEDUCTAL GRAY AND NUCLEUS OF THE SOLITARY TRACT EXPRESS FOS AFTER NOXIOUS STIMULATION OF THE STOMACH AND INTESTINES IN THE RAT

为研究中脑导水管周围灰质（PAG）与孤束核（NTS）内脏伤害性信息传递和调控之间的相互关系，采用免疫荧光组织化学方法结合荧光金（FG）逆行追踪技术，观察了大鼠NTS和PAG之间相互投射神经元在给予胃肠道伤害性刺激后的FOS表达情况。给胃肠道以1％多聚甲醛的伤害性刺激后，FOS阳性细胞主要出现于中尾段NTS的内侧亚核；在PAG内，则主要出现于足段PAG的腹外侧区。将FG微量注射于PAG后，再给予动物刺激，发现NTS内部分FG逆行标记细胞同时为FOS阳性，它们主要分布于中尾段NTS的内侧亚核，双标细胞占FG标记细胞的十分之一左右。同上，将FG注射于中尾段NTS后再施予伤害性刺激，在PAG内发现有FOS阳性的FG道标细胞，它们集中分布于尾段PAG的腹外侧区，双标细胞约占FG标记细胞的五分之一。此外，在中缝背核内也发现有一定数且的双标细胞。本文结果提示PAG可能对NTS内内脏伤害性信息的传递具有调控作用。

In order to study the relationship of the midbrain periaqueductal gray (PAG) with transmission and modulation of the visceral noxious information in the nucleus of the solitary tract (NTS), we examined FOS expression in the reciprocal projection neurons between the PAG and NTS using fluorescence immunohischemistry combined with fluorogold (FG) retrograde tracing. FOS expression was induced by noxious stimulation of the stomach and intestines with 1% para formaldehyde in the rat. FOS-like immunoreactive (-LI)neurons were mainly distributed in the medial subnucleus of the NTS at its middle and caudal levels. In the PAG, most of FOS-LI neurons were found in the ventrolateral region. After microinjection of FG into the PAG and then treated the rats with para formaldehyde, it was shown that about one tenth of FG-labeled neurons in the NTS expressed FOS;most of them were seen in the medial subnucleus of the NTS. Silmilarly,microinjection of the FG into the middle and caudal parts of the NTS, and approximately one fifth of FG-labeled neurons in the PAG expressed FOS; they were only observed in the ventrolateral region of the PAG. In addition,some of double-labeled neurons were found in the dorsal raphe nucleus. The present results suggest that the PAG may have modulatory effects on the transmission of the visceral nociceptive information in the NTS.