Cheng Z, Powley T L, Schwaber J S, Doyle F J
School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47097, USA.
J Comp Neurol. 1997 Apr 28;381(1):1-17. doi: 10.1002/(sici)1096-9861(19970428)381:1<1::aid-cne1>3.0.co;2-5.
We have used confocal microscopy to analyze the vagal afferent innervation of the rat heart. Afferents were labeled by injecting 1,1'-dioleyl-3,3,3',3'-tetramethylindocarbocyanine methanesulfonate (DiI) into the nodose ganglia of animals with prior supranodose de-efferentations, autonomic ganglia were stained with Fluoro-gold, and tissues were examined in whole mounts. Distinctively different fiber specializations were observed in the epi-, myo-, and endocardium: Afferents to the epicardium formed complexes associated with cardiac ganglia. These ganglia consisted of four major ganglionated plexuses, two on each atrium, at junctions of the major vessels with the atria. Ganglionic locations and sizes (left > right) were consistent across animals. In addition to principal neurons (PNs), significant numbers of small intensely fluorescent (SIF) cells were located in each of these plexuses, and vagal afferents provided dense pericellular varicose endings around the SIF cells in each ganglionic plexus, with few if any terminations on PNs. In the myocardium, vagal afferents formed close contacts with cardiac muscles, including conduction fibers. In the endocardium, vagal fibers formed "flower-spray" and "end-net" terminals in connective tissue. With three-dimensional reconstruction of confocal optical sections, a novel polymorphism was seen: Some fibers had one or more collaterals ending as endocardial flower sprays and other collaterals ending as myocardial intramuscular endings. Some unipolar or pseudounipolar neurons within each cardiac ganglionic plexus were retrogradely labeled from the nodose ganglia. In conclusion, vagal afferents form a heterogeneity of differentiated endings in the heart, including structured elements which may mediate chemoreceptor function, stretch reception, and local cardiac reflexes.
我们利用共聚焦显微镜分析了大鼠心脏的迷走神经传入神经支配。通过向先前进行过结上神经传出纤维切断术的动物的结状神经节内注射1,1'-二油酰基-3,3,3',3'-四甲基吲哚羰花青甲磺酸盐（DiI）来标记传入神经，用荧光金对自主神经节进行染色，并对组织进行整装观察。在心外膜、心肌和心内膜中观察到明显不同的纤维特化：传入心外膜的神经形成与心脏神经节相关的复合体。这些神经节由四个主要的神经节丛组成，每个心房各有两个，位于主要血管与心房的交界处。神经节的位置和大小（左>右）在不同动物之间是一致的。除了主要神经元（PNs）外，每个这些神经丛中都有大量小而强荧光（SIF）细胞，迷走神经传入神经在每个神经节丛中的SIF细胞周围提供密集的细胞周曲张终末，而在PNs上几乎没有终末。在心肌中，迷走神经传入神经与心肌，包括传导纤维形成紧密接触。在心内膜中，迷走神经纤维在结缔组织中形成“花束状”和“终网”终末。通过共聚焦光学切片的三维重建，发现了一种新的多态性：一些纤维有一个或多个侧支以心内膜花束状终末结束，而其他侧支以心肌肌内终末结束。每个心脏神经节丛中的一些单极或假单极神经元从结状神经节被逆行标记。总之，迷走神经传入神经在心脏中形成了异质性的分化终末，包括可能介导化学感受器功能、牵张感受和局部心脏反射的结构成分。
