Ahmed A, Johansson O, Folan-Curran J
Department of Anatomy, University College Galway, Ireland.
J Anat. 1997 Nov;191 ( Pt 4)(Pt 4):547-60. doi: 10.1046/j.1469-7580.1997.19140547.x.
The distribution of nerves immunoreactive to protein gene product 9.5 (PGP 9.5), tyrosine hydroxylase (TH), neuropeptide Y (NPY), substance P (SP) and calcitonin gene related peptide (CGRP) antisera was investigated in the atrioventricular valves of the Sprague-Dawley rat and the Dunkin-Hartley guinea pig using confocal and epifluoresence microscopy. No major differences were noted between the innervation of the mitral and tricuspid valves in either species. For all antisera the staining was more extensive in the guinea pig valves. Two distinct nerve plexuses separated by a 'nearly nerve free' zone were identified in both species with each antiserum tested. This was most apparent on the anterior cusp of the mitral valve. The major nerve plexus extends from the atrioventricular ring through the basal, intermediate and distal zones of the valves towards the free edge of the valve cusp. These nerve bundles, arranged as primary, secondary and tertiary components, ramify to the free edge of the valve and extend to the attachment of the chordae. They do not contribute to the innervation of the chordae tendineae. The second, minor chordal plexus, runs from the papillary muscles through the chordae tendineae and passes parallel to the free edge of the cusp. The nerves of this minor plexus are interchordal, branching to terminate mainly in the distal zone, free edge of the valve cusp and adjacent chordae tendineae. Some interchordal nerve fibres loop from a papillary muscle up through a chorda, along the free edge and pass down an adjacent chorda into another papillary muscle. The nerve fibres of the major and minor plexuses intermingle although no evidence was found for interconnectivity between them. In the distal zone between the major plexus which extends from the base of the valve and the minor chordal plexus there is a zone completely free of nerves staining with antisera to TH and NPY. Occasional nerves which stained positive for PGP 9.5, SP and CGRP immunoreactivities crossed this 'nearly nerve free zone' passing either from the chordal/free edge nerves to the intermediate and basal zones or vice versa. An additional small nerve plexus which displayed immunoreactivity to CGRP antiserum extended from the atrioventricular ring into the basal zone of the valve cusp. Not all chordae tendineae displayed immunoreactive nerve fibres. It is concluded that the innervation patterns of the sensory and sympathetic neurotransmitters and neuropeptides examined in the atrioventricular valves of the rat and guinea pig are ubiquitous in nature. The complexity of the terminal innervation network of the mammalian atrioventricular valves and chordae tendineae may contribute to the complex functioning of these valves in the cardiac cycle.
利用共聚焦显微镜和落射荧光显微镜，研究了蛋白质基因产物9.5（PGP 9.5）、酪氨酸羟化酶（TH）、神经肽Y（NPY）、P物质（SP）和降钙素基因相关肽（CGRP）抗血清免疫反应性神经在Sprague-Dawley大鼠和Dunkin-Hartley豚鼠房室瓣中的分布。在这两个物种中，二尖瓣和三尖瓣的神经支配未见明显差异。对于所有抗血清，豚鼠瓣膜中的染色更为广泛。在测试的每种抗血清中，在两个物种中均识别出两个由“几乎无神经”区域分隔的不同神经丛。这在二尖瓣前叶最为明显。主要神经丛从房室环穿过瓣膜的基部、中间和远端区域，朝向瓣膜叶的游离缘延伸。这些神经束排列为一级、二级和三级成分，分支至瓣膜的游离缘并延伸至腱索的附着处。它们对腱索的神经支配没有贡献。第二个较小的腱索神经丛从乳头肌穿过腱索，并与瓣膜叶的游离缘平行延伸。这个较小神经丛的神经位于腱索之间，主要分支终止于远端区域、瓣膜叶的游离缘和相邻的腱索。一些腱索间神经纤维从一个乳头肌向上穿过一条腱索，沿着游离缘，再向下穿过相邻的腱索进入另一个乳头肌。主要和较小神经丛的神经纤维相互交织，尽管未发现它们之间存在相互连接的证据。在从瓣膜基部延伸的主要神经丛和较小的腱索神经丛之间的远端区域，有一个完全没有用TH和NPY抗血清染色的神经的区域。偶尔有对PGP 9.5、SP和CGRP免疫反应呈阳性的神经穿过这个“几乎无神经区域”，要么从腱索/游离缘神经到中间和基部区域，反之亦然。另一个对CGRP抗血清显示免疫反应性的小神经丛从房室环延伸到瓣膜叶的基部区域。并非所有腱索都显示有免疫反应性神经纤维。结论是，在大鼠和豚鼠房室瓣中检测到的感觉和交感神经递质及神经肽的神经支配模式在本质上是普遍存在的。哺乳动物房室瓣和腱索的终末神经支配网络的复杂性可能有助于这些瓣膜在心动周期中的复杂功能。
