Dec 19, 2007

Connexin 43 expression delineates two discrete pathways in the human atrioventricular junction

The Anatomical Record : Advances in Integrative Anatomy and Evolutionary Biology
William J HuckerI R Efimov


Gap junction expression has been studied in the atrioventricular junction (AVJ) of many species, however, their distribution in the human AVJ is unknown. The AVJ expression of the gap junction protein connexin 43 (Cx43) is species dependent; therefore we investigated its distribution in the human AVJ. Using Masson trichrome histology, we reconstructed the AVJ of three normal human hearts and one with dilated cardiomyopathy in three dimensions. Cx43 was immunolabeled with vimentin and alpha-actinin to determine the cellular origin of Cx43 and was quantified in the following structures: interatrial septum (IAS), His bundle, compact node (CN), lower nodal bundle (LNB), leftward and rightward nodal extensions (LE and RE), and inferior, endocardial, and left-sided transitional cells. Histology revealed two nodal extensions in three of four hearts. Cx43 was found in the myocytes, but not fibroblasts, of the AVJ. LE and CN Cx43 was lower than the IAS (P < 0.05) and the RE, LNB, and His all expressed Cx43 similarly, with approximately half of IAS expression (RE: 44 +/- 36%; LNB: 50 +/- 26%; His: 48 +/- 12%, P = NS compared with IAS). Cx43 levels in transitional cells were similar to the IAS (P = not significant). Cx43 was found in myoc...Continue Reading

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Mentioned in this Paper

Immunofluorescence Assay
Biochemical Pathway
VIM gene
Histology Procedure
Specimen Type - Fibroblasts
Methyl Green
GJA1 gene
Muscle Cells
Trichrome stain

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