| First Author | Wang F | Year | 2013 |
| Journal | J Mol Cell Cardiol | Volume | 62 |
| Pages | 122-30 | PubMed ID | 23743021 |
| Mgi Jnum | J:225395 | Mgi Id | MGI:5693217 |
| Doi | 10.1016/j.yjmcc.2013.05.016 | Citation | Wang F, et al. (2013) T-type Ca(2)(+) channels regulate the exit of cardiac myocytes from the cell cycle after birth. J Mol Cell Cardiol 62:122-30 |
| abstractText | T-type Ca(2+) channels (TTCCs) are expressed in the fetal heart and then disappear from ventricular myocytes after birth. The hypothesis examined in this study was the alpha1G TTCCs' influence in myocyte maturation and their rapid withdrawal from the cell cycle after birth. METHODS: Cardiac myocytes were isolated from neonatal and adult wild type (WT), alpha1G-/- and alpha1G over expressing (alpha1GDT) mice. Bromodeoxyuridine (BrdU) uptake, myocyte nucleation, cell cycle analysis, and T-type Ca(2+) currents were measured. RESULTS: All myocytes were mono-nucleated at birth and 35% of WT myocytes expressed functional TTCCs. Very few neonatal myocytes had functional TTCCs in alpha1G-/- hearts. By the end of the first week after birth no WT or alpha1G-/- had functional TTCCs. During the first week after birth about 25% of WT myocytes were BrdU+ and became bi-nucleated. Significantly fewer alpha1G-/- myocytes became bi-nucleated and fewer of these myocytes were BrdU+. Neonatal alpha1G-/- myocytes were also smaller than WT. Adult WT and alpha1G-/- hearts were similar in size, but alpha1G-/- myocytes were smaller and a greater % were mono-nucleated. alpha1G over expressing hearts were smaller than WT but their myocytes were larger. CONCLUSIONS: The studies performed show that loss of functional TTCCs is associated with bi-nucleation and myocyte withdrawal from the cell cycle. Loss of alpha1G TTCCs slowed the transition from mono- to bi-nucleation and resulted in an adult heart with a greater number of small cardiac myocytes. These results suggest that TTCCs are involved in the regulation of myocyte size and the exit of myocytes from the cell cycle during the first week after birth. |
