| Autor: |
Yong-Fu Xiao, Tenbroek, Erica M., Wilhelm, Joshua J., Iaizzo, Paul A., Sigg, Daniel C. |
| Předmět: |
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| Zdroj: |
American Journal of Physiology: Cell Physiology; Sep2006, Vol. 291 Issue 3, pC407-C416, 10p, 2 Charts, 7 Graphs |
| Abstrakt: |
HL-5 cells are cultured murine atrial cardiomyocytes and have been used in studies to address important cellular and molecular questions. However, electrophysiological features of HL-5 cells have not been characterized. In this study, we examined such properties using whole cell patch-clamp techniques. Membrane capacitance of the HL-5 cells was from 8 to 62 pF. The resting membrane potential was -57.8 ± 1.4 mV (n = 51). Intracellular injection of depolarizing currents evoked action potentials (APs) with variable morphologies in 71% of the patched cells. Interestingly, the incidence of successful, current-induced APs positively correlated with the hyperpolarizing degrees of resting membrane potentials (r = 0.99, P < 0.001). Only a few of the patched cells (4 of 51, 7.8%) exhibited spontaneous APs. The muscarinic agonist carbachol activated the acetylcholine-activated K+ current and significantly shortened the duration of APs. Immunostaining confirmed the presence of the muscarinic receptor type 2 in FIL-5 cells. The hyperpolarization-activated cation current (It) was detected in 39% of the patched cells. The voltage to activate 50% of Ic channels was -73.4 ± 1.2 mV (n = 12). Voltage-gated Nat Ca2+ and K+ currents were observed iii the HL-5 cells with variable incidences. Compared with the adult mouse cardiomyocytes, the HL-5 cells had prolonged APs and small outward K+ currents. Our data indicate that HL-5 cells display significant electrophysiological heterogeneity of morphological appearance of APs and expression of functional ion channels. Compared with adult murine cardiomyocytes, HL-5 cells show an immature phenotype of cardiac AP morphology. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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