Table 3.
Voltage-gated Na+ current densities and properties in Fgf13fl/y and cFgf13KO adult mouse ventricular cardiomyocytes infected or not with WT or phosphomutant iFGF13-VY-expressing adenoviruses
| INa (pA/pF) | Time to peak (ms) | Time course of inactivation | Voltage dependence of activation | Voltage dependence of inactivation | Recovery from inactivation | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| τfast (ms) | τslow (ms) | Afast/Aslow | V1/2 (mV) | k (mV) | V1/2 (mV) | k (mV) | τfast (ms) | τslow (ms) | |||
| Fgf13 fl/y | −31.8 ± 1.4 (58) | 1.09 ± 0.03 (33) | 1.42 ± 0.05 (33) | 5.3 ± 0.3 (33) | 8.6 ± 1.0 (33) | −28.0 ± 0.5 (33) | 7.5 ± 0.1 (33) | −77.3 ± 0.7 (30) | 6.3 ± 0.2 (30) | 2.9 ± 0.1 (27) | 37.3 ± 1.2 (27) |
| cFgf13KO | −33.9 ± 2.0 (47) | 0.97 ± 0.03 (20) | 0.90 ± 0.02 (20) **** | 5.9 ± 0.2 (20) | 21.9 ± 1.1 (20) **** | −28.1 ± 0.4 (20) | 7.8 ± 0.1 (20) | −85.9 ± 0.6 (19) **** | 6.1 ± 0.2 (19) | 3.0 ± 0.1 (18) | 41.9 ± 2.6 (18) |
| cFgf13KO + iFGF13-VY-WT | −58.5 ± 5.3 (39) **** | 1.02 ± 0.03 (28) | 1.48 ± 0.06 (28) #### | 4.4 ± 0.2 (28) | 5.2 ± 0.4 (28) #### | −31.2 ± 0.5 (28) | 7.1 ± 0.2 (28) | −76.7 ± 0.6 (28) #### | 5.2 ± 0.1 (28) | 3.2 ± 0.2 (27) | 45.1 ± 2.5 (27) |
| cFgf13KO + iFGF13-VY-35-38A | −50.2 ± 3.3 (37) ** | 1.01 ± 0.02 (27) | 1.41 ± 0.05 (27) #### | 4.6 ± 0.1 (27) | 5.8 ± 0.6 (27) #### | −30.4 ± 0.7 (27) | 7.2 ± 0.2 (27) | −77.2 ± 0.7 (21) #### | 6.0 ± 0.2 (21) | 3.4 ± 0.2 (15) | 40.2 ± 1.8 (15) |
| cFgf13KO + iFGF13-VY-35-38E | −46.5 ± 2.5 (38) | 1.09 ± 0.04 (22) | 1.48 ± 0.05 (22) #### | 4.7 ± 0.2 (22) | 6.4 ± 0.7 (22) #### | −29.5 ± 0.4 (22) | 6.8 ± 0.1 (22) | −74.3 ± 0.7 (20) #### | 5.6 ± 0.2 (20) | 2.7 ± 0.1 (18) | 39.9 ± 2.8 (18) |
| cFgf13KO + iFGF13-VY-218A | −49.5 ± 2.4 (49) ** | 1.04 ± 0.02 (27) | 1.42 ± 0.04 (27) #### | 4.5 ± 0.1 (27) | 5.2 ± 0.4 (27) #### | −31.5 ± 0.4 (27) | 7.1 ± 0.1 (27) | −75.6 ± 0.5 (20) #### | 5.7 ± 0.1 (20) | 3.0 ± 0.2 (20) | 38.1 ± 2.1 (20) |
| cFgf13KO + iFGF13-VY-218E | −49.9 ± 2.3 (39) ** | 0.93 ± 0.04 (18) | 1.14 ± 0.07 (18) | 3.9 ± 0.2 (18) | 6.2 ± 1.3 (18) #### | −32.5 ± 0.5 (18) | 7.0 ± 0.16 (18) | −78.9 ± 1.6 (14) #### | 6.6 ± 0.4 (14) | 3.0 ± 0.2 (11) | 39.4 ± 2.5 (11) |
| cFgf13KO + iFGF13-VY-230-232A | −39.8 ± 2.7 (24) | 1.25 ± 0.05 (11) | 1.52 ± 0.11 (11) #### | 4.8 ± 0.2 (11) | 8.6 ± 1.6 (11) #### | −30.7 ± 0.5 (11) | 6.8 ± 0.2 (11) | −74.9 ± 0.6 (11) #### | 5.0 ± 0.1 (11) | 2.8 ± 0.1 (11) | 38.2 ± 3.3 (11) |
| cFgf13KO + iFGF13-VY-230-232E | −44.2 ± 2.6 (35) | 1.17 ± 0.03 (18) | 1.57 ± 0.06 (18) #### | 4.7 ± 0.2 (18) | 5.4 ± 0.5 (18) #### | −30.9 ± 0.5 (18) | 7.0 ± 0.2 (18) | −75.9 ± 0.5 (18) #### | 5.1 ± 0.1 (18) | 3.1 ± 0.1 (18) | 40.9 ± 2.3 (18) |
| cFgf13KO + iFGF13-VY-238-240A | −56.5 ± 2.4 (31) **** | 1.01 ± 0.03 (16) | 1.42 ± 0.04 (16) #### | 4.5 ± 0.2 (16) | 5.7 ± 0.7 (16) #### | −31.2 ± 0.4 (16) | 7.4 ± 0.2 (16) | −77.3 ± 0.9 (16) #### | 5.5 ± 0.2 (16) | 3.3 ± 0.3 (16) | 39.6 ± 2.6 (16) |
| cFgf13KO + iFGF13-VY-238-240E | −55.8 ± 3.5 (35) **** | 0.94 ± 0.03 (26) | 1.30 ± 0.06 (26) ### | 4.1 ± 0.2 (26) | 5.6 ± 0.6 (26) #### | −33.8 ± 0.9 (26) | 7.2 ± 0.2 (26) | −75.5 ± 0.9 (26) #### | 5.4 ± 0.2 (26) | 2.6 ± 0.2 (26) | 35.3 ± 1.8 (26) |
| cFgf13KO + iFGF13-VY-250-255A | −47.7 ± 3.0 (25) | 1.08 ± 0.04 (18) | 1.63 ± 0.07 (18) #### | 5.0 ± 0.3 (18) | 6.7 ± 0.9 (18) #### | −30.9 ± 0.7 (18) | 7.1 ± 0.2 (18) | −76.7 ± 0.7 (18) #### | 5.3 ± 0.2 (18) | 3.3 ± 0.3 (16) | 51.1 ± 4.0 (16) |
| cFgf13KO + iFGF13-VY-250-255E | −50.9 ± 3.0 (27) ** | 1.01 ± 0.02 (22) | 1.42 ± 0.08 (22) #### | 4.4 ± 0.4 (22) | 6.2 ± 1.7 (22) #### | −31.1 ± 0.5 (22) | 6.9 ± 0.2 (22) | −75.9 ± 0.5 (22) #### | 5.0 ± 0.1 (22) | 2.8 ± 0.1 (20) | 38.7 ± 2.0 (20) |
| cFgf13KO + iFGF13-VY-9A | −63.6 ± 2.9 (26) **** | 0.98 ± 0.03 (20) | 1.38 ± 0.08 (20) #### | 4.3 ± 0.2 (20) | 4.5 ± 0.4 (20) #### | −34.1 ± 0.5 (20) | 6.6 ± 0.2 (20) | −77.2 ± 0.5 (20) #### | 5.1 ± 0.1 (20) | 3.1 ± 0.2 (20) | 37.2 ± 1.5 (20) |
Whole-cell voltage-gated Na+ currents were recorded 48 h following isolation of control Fgf13 floxed (Fgf13fl/y) or cardiac specific Fgf13 knockout (cFgf13KO) adult mouse ventricular cardiomyocytes infected or not with WT, phosphosilent (mutation to alanine), or phosphomimetic (mutation to glutamate) iFGF13-VY-expressing adenoviruses using the protocols described in the Materials and methods section. The peak Na+ current (INa) density, time to peak INa, and time course of inactivation properties presented were determined from analyses of records obtained on depolarizations to −20 mV (HP = −120 mV). All values are means ± SEM. The number of cells analyzed is provided in parentheses. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 versus Fgf13fl/y; #P < 0.05, ##P < 0.01, ###P < 0.001, ####P < 0.0001 versus cFgf13KO; one-way ANOVA.