孤束核内儿茶酚胺能神经元汇聚内脏传入与口面部躯体伤害性信息并向臂旁核投射

CATECHOLAMINERGIC NEURONS IN NUCLEUS OF THE SOLITARY TRACT CONVERGE VISCERAL INPUTS AND OROFACIAL SOMATIC NOCICEPTIVE INFORMATION AND PROJECT TO PARABRACHIAL NUCLEUS IN RAT

为了研究内脏初级传入与口面部深层组织躯体伤害性信息是否汇聚于孤束核(NTS)中向臂旁核(PBN)投射的儿茶酚胺(CA)能神经元。本实验将SD大鼠随机分为两组。第一组动物以生物素化的葡聚糖胺(BDA)注入颈部迷走神经主干跨节追踪,四甲基罗达明(TMR)注入臂旁外侧核(LPB)逆行追踪,福尔马林刺激咬肌并行FOS的免疫荧光组织化学染色;第二组动物以BDA注入颈部迷走神经主干跨节追踪,福尔马林刺激咬肌并行FOS和酪氨酸羟化酶(TH)染色。在激光扫描共聚焦显微镜下对两组大鼠NTS内的标记细胞和纤维进行了观察。两组实验中,主要在NTS的内侧、中间内侧和连合亚核内观察到重叠分布的TMR、FOS或TH、FOS单标神经元。其中部分TMR逆行标记的或TH阳性神经元呈FOS阳性并与BDA跨节标记的纤维和终末形成紧密接触。提示大鼠NTS内的CA能神经元可能汇聚了内脏初级传入和口面部深层组织的躯体伤害性刺激信息并向LPB投射。

The purpose of the present study was to investigate if the visceral primary afferents and noeiccptive information from orofacial deep tissue converge onto the catecholaminergic neurons projecting to the parabrachial nucleus （PBN） in the nucleus of the solitary tract （NTS）. SD rats were randomly divided into two groups. In the first group, ipsilateral injections of tetramethyl rhodamine （TMR） into the lateral parabrachial nucleus （LPB） and biotinylated dextran amine （BDA） into the cervical trunk of vagus nerve were made to retrogradely label the neurons and transganglionicly label the fibers/terminals in NTS, respectively. In addition, nociceptive response of retrograde-labeled neurons were detected by immunofluorescent staining of FOS protein following injection of formalin into masseter muscle. In the second group, BDA and formalin were ipsilaterally injected into cervical trunk of vagus nerve and into masseter muscle, respectively; and immunofluorescent histochemistry for tyrosin hydroxylase （TH） and FOS protein was performed. Finally, the labeled neurons and fibers were observed under laser scanning confocal microscope. In the two groups, TMR,FOS or TH ,FOS single-labeled neurons were mainly overlapped in medial, intermedial and commissural subnuclei of NTS. Some TMR retrograde-labeled or TH-immunoreactive neurons were also positive for FOS protein. Immunolabeled terminals/fibers from vagus afferent inputs made close connection to the TH/FOS or TMR/FOS double- labeled neurons in the subnuclei mentioned above. These results indicate that the eatecholaminergic neurons of NTS might converge visceral primary afferents and somatic noeiceptive information from orofacial deep tissue and ascendingly project to LPB.