Ulphani Joseph S, Arora Rishi, Cain Jack H, Villuendas Roger, Shen Sharon, Gordon David, Inderyas Firdous, Harvey Laura A, Morris Alexander, Goldberger Jeffrey J, Kadish Alan H
Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
Am J Physiol Heart Circ Physiol. 2007 Sep;293(3):H1629-35. doi: 10.1152/ajpheart.00139.2007. Epub 2007 Jun 1.
The objective of the study was to investigate the morphology, distribution, and electrophysiological profile of the autonomic fibers that innervate the ligament of Marshall (LOM). Gross anatomical dissections were performed in 10 dogs. Sections of the left vagus nerve, left stellate ganglion, and the LOM were immunostained to identify adrenergic and cholinergic nerves. Hearts were also stained for acetylcholinesterase to identify epicardial cholinergic nerves. In vivo electrophysiological studies were performed in another 10 dogs before and after LOM ablation. The anatomical examination revealed that the LOM is innervated by a branch of the left vagus. Immunohistochemistry confirmed that these nerve bundles are predominantly cholinergic (cholinergic-to-adrenergic ratio of 12.6 +/- 3.9:1). Cholinergic nerves originating in the LOM were found to innervate surrounding left atrial structures, including the pulmonary veins, left atrial appendage, coronary sinus, and posterior left atrial fat pad. Ablation of the LOM significantly attenuated effective refractory period shortening at distant sites, such as pulmonary veins and left atrial appendage, in response to vagal stimulation (vagal-induced ERP decrease in the left atrium: baseline vs. postablation = 17 vs. 4%; P = 0.0056). In conclusion, the LOM contains a predominance of cholinergic nerve fibers. Cholinergic fibers arising from the LOM innervate surrounding structures and contribute to the electrophysiological profile of the left atrium. These findings may provide a basis for the role of the LOM in the genesis and maintenance of atrial fibrillation.
本研究的目的是调查支配马歇尔韧带（LOM）的自主神经纤维的形态、分布和电生理特征。对10只犬进行大体解剖。对左迷走神经、左星状神经节和LOM切片进行免疫染色，以识别肾上腺素能神经和胆碱能神经。心脏也用乙酰胆碱酯酶染色，以识别心外膜胆碱能神经。在另外10只犬身上，在LOM消融前后进行体内电生理研究。解剖学检查显示，LOM由左迷走神经的一个分支支配。免疫组织化学证实，这些神经束主要是胆碱能的（胆碱能与肾上腺素能的比例为12.6±3.9:1）。发现起源于LOM的胆碱能神经支配周围的左心房结构，包括肺静脉、左心耳、冠状窦和左心房后脂肪垫。LOM消融显著减弱了远处部位（如肺静脉和左心耳）对迷走神经刺激的有效不应期缩短（左心房迷走神经诱导的ERP降低：消融前与消融后=17%对4%；P=0.0056）。总之，LOM中胆碱能神经纤维占优势。起源于LOM的胆碱能纤维支配周围结构，并对左心房的电生理特征有贡献。这些发现可能为LOM在心房颤动的发生和维持中的作用提供依据。
