Yasuhara Osamu, Matsuo Akinori, Bellier Jean-Pierre, Aimi Yoshinari
Molecular Neuroscience Research Center, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu 520-2192, Japan.
J Histochem Cytochem. 2007 Mar;55(3):287-99. doi: 10.1369/jhc.6A7092.2006. Epub 2006 Dec 1.
Cholinergic innervation of the heart has been analyzed using cholinergic markers including acetylcholinesterase, choline acetyltransferase (ChAT), and vesicular acetylcholine transporter (VAChT). In the present study we demonstrate putative cholinergic nerves in the rat heart using an antibody to ChAT of a peripheral type (pChAT), which is the product of a splice variant of ChAT mRNA and preferentially localized to peripheral cholinergic nerves. Expression of mRNAs for pChAT and the conventional form of ChAT (cChAT) were verified in the rat atrium by RT-PCR. Localization of both protein products in the atrium was confirmed by Western blotting. Virtually all neurons and small intensely fluorescent cells in the intrinsic cardiac ganglia were stained immunohistochemically for pChAT. The density of pChAT-positive fibers was very high in the conducting system, high in both atria, the right atrium in particular, and low in the ventricular walls. pChAT and VAChT immunoreactivities were closely associated in some fibers and fiber bundles in the ventricular walls. These results indicate that intrinsic cardiac neurons homogeneously express both pChAT and cChAT. Furthermore, innervation of the ventricular walls by pChAT- and VAChT-positive fibers provides morphological evidence for a significant role of cholinergic mechanisms in ventricular functions.
已使用包括乙酰胆碱酯酶、胆碱乙酰转移酶（ChAT）和囊泡乙酰胆碱转运体（VAChT）在内的胆碱能标记物对心脏的胆碱能神经支配进行了分析。在本研究中，我们使用针对外周型ChAT（pChAT）的抗体在大鼠心脏中证实了假定的胆碱能神经，pChAT是ChAT mRNA剪接变体的产物，优先定位于外周胆碱能神经。通过逆转录聚合酶链反应（RT-PCR）在大鼠心房中验证了pChAT和传统形式的ChAT（cChAT）的mRNA表达。通过蛋白质印迹法证实了两种蛋白质产物在心房中的定位。实际上，心脏固有神经节中的所有神经元和小而强荧光细胞均通过免疫组织化学法对pChAT进行了染色。pChAT阳性纤维的密度在传导系统中非常高，在两个心房中都很高，尤其是右心房，而在心室壁中则很低。在心室壁的一些纤维和纤维束中，pChAT和VAChT免疫反应性密切相关。这些结果表明，心脏固有神经元均一性地表达pChAT和cChAT。此外，pChAT和VAChT阳性纤维对心室壁的神经支配为胆碱能机制在心室功能中发挥重要作用提供了形态学证据。
