Differential expression of connexin43 gap junctions in cardiomyocytes isolated from canine thoracic veins.
We investigated the phenotypic features of cardiomyocytes, including the gap junctions, in the myocardial sleeve of thoracic veins. Single cardiomyocytes, isolated from the canine pulmonary veins (PV) and superior vena cava (SVC) using digestive enzymes, were examined by immunoconfocal microscopy using antisera against connexin43 (Cx43), Cx40, and other cell markers. The results showed that isolated cardiomyocytes displayed rod shapes of various sizes, ranging from <50 microm to >200 microm in length, and all the cells expressed alpha-actinin and vinculin. Gap junctions made of various amounts of Cx43 and Cx40 were found at the cell borders. These two connexins were extensively co-localized. Comparison between the thoracic veins showed that cells of the SVC contained more Cx43 gap junctions (total Cx43 gap junctions area per cell surface area, 4.0 +/- 0.2% vs 1.5 +/- 0.2%; p<0.01). In addition, for single-nucleus cells, those from the PV were longer (103.7 +/- 3.6 vs 85.0 +/- 3.1 microm; p<0.01) but narrower (14.4 +/- 0.5 vs 16.9 +/- 0.9 microm; p<0.01). In conclusion, canine thoracic veins contain cardiomyocytes with differences in shape and gap junctions, suggesting that the electrical conduction properties may be different between the thoracic veins.
Yeh
Hung-I
HI
Department of Internal Medicine, Mackay Memorial Hospital and Mackay Junior College of Nursing, Taipei, Taiwan.
Lai
Yu-Jun
YJ
Lee
Yi-Nan
YN
Chen
Yi-Jen
YJ
Chen
Yao-Chang
YC
Chen
Chih-Chun
CC
Chen
Shih-Ann
SA
Lin
Cheng-I
CI
Tsai
Cheng-Ho
CH
D000818:Animals; D018031:Connexin 43 / Q000096:biosynthesis* / Q000276:immunology; D003331:Coronary Vessels / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D004285:Dogs; D017629:Gap Junctions / Q000378:metabolism*; D007106:Immune Sera; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D032342:Muscle Cells / Q000378:metabolism* / Q000648:ultrastructure; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D011667:Pulmonary Veins / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure; D013909:Thorax; D014683:Vena Cava, Superior / Q000166:cytology / Q000378:metabolism / Q000648:ultrastructure
D018031:Connexin 43; D007106:Immune Sera