Table 2.

Pacemaker activity and action potential properties in SAN cells of control and mutant mice

Action potential parameterControls
nMutants
nP
SAN cellsSAN cells
Rate, bpm247 ± 1615165 ± 3210.0209
Action potential amplitude, mV81 ± 41583 ± 310.8228
Minimum diastolic potential, mV−58 ± 115−51 ± 210.0036
Action potential duration, ms112 ± 515150 ± 1510.0139
Action potential threshold, mV−45 ± 215−35 ± 910.1821
Slope of the diastolic depolarization, V/S0.084 ± 0.014150.019 ± 0.00710.0014
  • This table shows basal cellular pacemaker activity in the absence of ISO stimulation. Thus SAN cell firing rates differ from those shown in Fig. 3C. Cells from mutant animals that were completely quiescent (n = 5) and cells in which the slope of diastolic depolarization was too low to allow accurate measurement (n = 3) were excluded from this analysis. Differences in parameters between groups were tested using an unpaired Student t test. Values are given as mean ± SEM.