Differential subunit composition of the G protein–activated inward-rectifier potassium channel during cardiac development
J. Clin. Invest. Bernd K. Fleischmann, et al. 114:994 doi:10.1172/JCI15925 [Go to this article.]

Figure 3
I_K,ACh density, M2 receptor expression, and G_i/G_o-protein content in atrial cardiomyocytes during embryonic development. (A) Density of I_K,ACh determined at a holding potential of _70 mV is identical at the two differentiation stages. Extracellular K⁺ was 30 mM, and data are mean ± SEM of 12 early- and 9 late-stage cardiomyocytes (P = 0.9, unpaired Student’s t test). (B) M2 receptor expression in early- and late-stage atria determined from binding experiments with [-]-[³H]QNB. Data are mean ± SD of 3 early- and 2 late-stage cell preparations (P = 0.002, unpaired Student’s t test). (C) G_i/G_o-protein content of atrial membranes determined by [³²P]ADP-ribosylation analyzed densitometrically. One of 2 independent experiments with identical results is shown. Comparable protein loading was confirmed with Coomassie staining. Asterisk denotes statistically significant difference. Sta., standard.