Cheng Z, Powley T L, Schwaber J S, Doyle F J
Department of Psychological Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
J Comp Neurol. 1999 Jul 26;410(2):320-41.
We injected the anterograde fluorescent tracer 1,1'-dioleyl-3,3,3',3'-tetramethylindocarbocyanine methanesulfonate (DiI) into the dorsal motor nucleus of the vagus (DmnX), counterstained the cardiac ganglia with Fluorogold (FG), and used confocal microscopy to examine the distributions and different types of DmnX fibers in wholemounts of the atria. We also quantified the number of DmnX cardiac axons and the number of innervated cardiac principal neurons (PNs). Rats with unilateral DiI injections were used in three different experiments, including unilateral FG soaking of cervical vagal trunks, intracranially rhizotomizing the vagal afferent roots, or contralaterally sectioning the cervical vagus. These manipulations indicated that DiI-labeled cardiac fibers were exclusively from the DmnX. Our observations established that: (1) three major ganglionic plexuses were localized in the epicardium; (2) both sides of the DmnX supplied significant fibers to each of the plexuses; (3) these cardiac efferents formed dense basket terminals around individual PNs; (4) collaterals of individual DmnX fibers diverged, producing calyx endings on multiple PNs; (5) small intensely fluorescent (SIF) cells in the cardiac plexuses were innervated pericellularly; (6) individual axons could innervate both PNs and SIF cells; (7) the total number of DmnX fibers were in the range of [68, 96; left] and [67, 115; right]; (8) these fibers innervated 709 (left) and 494 (right), or at least 18% and 12%, of the PNs, respectively; and (9) vagal preganglionics exhibited a degree of lateralization: Significantly more PNs were contacted by fiber varicosities in the sinoatrial plexus than in the atrioventricular plexus after right DmnX injections. In summary, the present observations suggest that the DmnX plays a significant role(s) in controlling the heart.
我们将顺行性荧光示踪剂1,1'-二油酰基-3,3,3',3'-四甲基吲哚羰花青甲磺酸盐（DiI）注入迷走神经背运动核（DmnX），用荧光金（FG）对心脏神经节进行复染，并使用共聚焦显微镜检查心房整装标本中DmnX纤维的分布和不同类型。我们还对DmnX心脏轴突的数量和受支配的心脏主神经元（PNs）的数量进行了量化。单侧注射DiI的大鼠用于三个不同的实验，包括单侧FG浸泡颈迷走神经干、颅内切断迷走神经传入根或对侧切断颈迷走神经。这些操作表明，DiI标记的心脏纤维仅来自DmnX。我们的观察结果表明：（1）三个主要的神经节丛位于心外膜；（2）DmnX的两侧向每个丛提供大量纤维；（3）这些心脏传出纤维在单个PNs周围形成密集的篮状终末；（4）单个DmnX纤维的侧支发散，在多个PNs上产生花萼样终末；（5）心脏丛中的小而强荧光（SIF）细胞被细胞周围神经支配；（6）单个轴突可支配PNs和SIF细胞；（7）DmnX纤维的总数在[68, 96；左侧]和[67, 115；右侧]范围内；（8）这些纤维分别支配709个（左侧）和494个（右侧）PNs，或至少分别支配18%和12%的PNs；（并且）（9）迷走神经节前神经元表现出一定程度的侧化：右侧DmnX注射后，窦房结丛中纤维膨体接触的PNs明显多于房室丛。总之，目前的观察结果表明DmnX在控制心脏方面发挥着重要作用。
