Table 1. K_ATP currents in embryonic myocytes.

K_ATP currents (number of cells (#) and current density), as assessed by whole cell recordings, at different developmental stages (9.5–17.5 dpc) in the WT and overexpressed STG embryonic cardiomyocytes. n represents number of embryos. N represents number of pregnancies. K_ATP positive cells (using cutoff value of <0.5 pA/pF as lack of K_ATP), demonstrated either basal (immediately after breaking in), spontaneously activating (without pinacidil exposure), or as a result of pharmacologic activation by pinacidil and inhibition by glibenclamide. Cells that demonstrated no K_ATP even after exposure to pinacidil for > 60 seconds, were designated K_ATP-negative cells. Cells that did not demonstrate K_ATP, but were exposed to pinacidil for less than 60 seconds were designated as undetermined (UD).

Genotype	KATP positive cells	KATP Negative cells	Basal/spontaneous KATP # of cells (Basal current density, pA/pF)	Peak KATP # of cells (Peak current densilty, pA/pF)	UD cells	Total n/N
WT	11	15	7 (1.4±0.6)	26 (11.2±5)	50	76/10
Line 4	13	6	6 (5.8±2.9)	19 (10.6±3.3)	19	38/7
Line 720	0	4	0	0	12	16/3