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Ultrastructure and immunohistochemistry of innervation in the regions of the mouse sinuatrial and atrioventricular nodes
Author(s) -
Rysevaite Kristina,
Jokubauskas Marius,
Saburkina Inga,
Pauziene Neringa,
Pauza Dainius H.
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.726.6
Subject(s) - choline acetyltransferase , immunohistochemistry , atrioventricular node , cholinergic , ganglion , electrical conduction system of the heart , anatomy , tyrosine hydroxylase , ultrastructure , nerve plexus , bundle branches , myocyte , free nerve ending , pathology , biology , chemistry , microbiology and biotechnology , medicine , neuroscience , tachycardia , electrocardiography
The study was aimed to examine (1) the ultrastructure of innervation in regions of atrioventricular and sinuatrial nodes, and (2) the density of nerve fibers in these regions comparing images of fluorescent immunohistochemistry and transmission electron microscopy. The expression and distribution of adrenergic, cholinergic nerve fibers and conductive cardiac myocytes within the correspondent heart regions were respectively determined applying immunohistochemistry for tyrosine hydroxylase (TH), choline acetyltransferase (ChAT), and hyperpolarization activated cyclic nucleotide‐gated potassium channel 4. Both the electron microscopy and immunohistochemistry of the sampled conventional regions of the SA and AV nodes demonstrate the dense meshwork of ChAT(+) and TH(+) nerve fibers, but ChAT(+) nerve fibers are evidently predominant therein. The examined nerve samples involved exclusively the unmyelinated nerve fibers, in which many axons possessed varicosities with mediatory vesicles. Some conductive myocytes in atrioventricular node were in close contacts with axons. Electron microscopy and immunohistochemistry for adrenergic and cholinergic neuronal markers confirm the densest and extremely complex networks of nerve fibers in the regions of the sinuatrial and atrioventricular nodes compared with the adjacent cardiac zones. Such morphologic pattern of innervation implies a complex neural control of the mouse cardiac conduction system. This study was supported by the Research Council of Lithuania (No. MIP‐11184).