Table 2.

Effects of isoproterenol on I_pump in WT and PLM-KO myocytes

	WT	PLM-KO
[Na+]pip = 80 mM
Ipump	0.90 ± 0.08 (5)	1.27 ± 0.07* (6)
Iα1	0.74 ± 0.08	1.10 ± 0.09*
Iα2	0.16 ± 0.01	0.16 ± 0.03
ΔIα1	0.54 ± 0.20	0.11 ± 0.06*
ΔIα2	0.05 ± 0.03	0.07 ± 0.05
[Na+]pip = 10 mM
Ipump	0.40 ± 0.05 (5)	0.40 ± 0.05 (5)
Iα1	0.34 ± 0.04	0.34 ± 0.04
Iα2	0.06 ± 0.02	0.06 ± 0.01
ΔIα1	0.16 ± 0.02	0.03 ± 0.02*
ΔIα2	0.03 ± 0.04	0.00 ± 0.03

Values are means ± SE for no. of myocytes in parentheses. [Na⁺]_pip, pipette Na⁺ concentration; I_α1 and I_α2, current densities (pA/pF) of α₁- and α₂-subunits of Na⁺-K⁺-ATPase, respectively; I_pump, total current density of Na⁺-K⁺-ATPase; ΔI_α1 and ΔI_α2, steady-state changes in I_α1 and I_α2, respectively, in response to isoproterenol (1 μM).

^*P < 0.02, WT vs. PLM-KO.