TABLE 2

Voltage and kinetic parameters of recombinant Ca_V3 channels in the absence and the presence of amiloride

Data represent mean ± S.E.M. V₅₀, k, and V_rev are given in millivolts and were obtained from I-V relationship fits with the modified Boltzmann functions. τ_act and τ_inact are shown in ms, and were obtained from two exponential fits of current recordings at −30 mV. τ_h (in milliseconds) was obtained from single exponential fits to the recovery from inactivation data at −100 and −70 mV. Recovery data are given as the maximum fraction of current recovered after the longest time interval between both pulses to −30 mV. The number of investigated cells was 8 for Ca_V3.1, 11 for Ca_V3.2, and 6 for Ca_V3.3 channels, except for the recovery data, for which the numbers of cells were five, four, and six for −100 mV and five, three, and three for −70 mV, respectively.

	Ca_V3.1		Ca_V3.2		Ca_V3.3
	Control	AMI	Control	AMI	Control	AMI
V₅₀	−48.0 ± 0.6	−47.7 ± 0.7	−48.3 ± 0.8	−46.5 ± 0.9	−42.3 ± 0.6	−34.8 ± 0.7^*
k	5.2 ± 0.1	5.7 ± 0.1	5.4 ± 0.1	6.2 ± 0.1	5.6 ± 0.2	6.8 ± 0.2
V_rev	26.7 ± 0.9	25.3 ± 0.9	32.2 ± 0.7	30.9 ± 0.7	31.6 ± 0.4	33.9 ± 0.4
τ_act	2.9 ± 0.2	4.1 ± 0.2^*	5.2 ± 0.4	5.1 ± 0.3	21.3 ± 1.6	29.9 ± 1.9^*
τ_inact	18.5 ± 0.9	21.5 ± 1.2	15.5 ± 0.8	22.1 ± 1.2^*	44.9 ± 1.2	73.3 ± 2.1^*
τ_h at −100 mV	135 ± 4	430 ± 28^*	344 ± 13	370 ± 18	441 ± 24	661 ± 58^*
Rec at −100 mV	0.99 ± 0.01	0.91 ± 0.02^*	0.97 ± 0.01	0.94 ± 0.01^*	1.1 ± 0.02	0.89 ± 0.04^*
τ_h at −70 mV	287 ± 20	549 ± 151^*	800 ± 26	687 ± 153	1148 ± 77	1535 ± 226^*
Rec at −70 mV	0.15 ± 0.02	0.13 ± 0.02	0.13 ± 0.02	0.12 ± 0.02	0.17 ± 0.02	0.32 ± 0.04^*

Rec, recovery.
↵* Significantly different from control (P < 0.05).