Journal: The Journal of General Physiology

Article Title: Beat-locked ATP microdomains in the sinoatrial node map a Ca 2+ -timed energetic hierarchy and regional pacemaker roles

doi: 10.1085/jgp.202513874

Figure Lengend Snippet: SR Ca 2+ release drives beat-to-beat ATP oscillations, while I f modulates metabolic frequency. (A) Representative normalized cyto-iATP confocal line-scan traces from superior (top) and inferior (bottom) SA nodes acquired under control conditions (left), after I f inhibition with ivabradine (30 µM; middle), and following SERCA inhibition with thapsigargin (1 µM; right). Traces are shown as normalized fluorescence (F/F 0 ). The dashed line indicates baseline fluorescence (F/F 0 = 1). (B and C) Summary quantification of cyto-iATP oscillation frequency (B) and peak cyto-iATP oscillation amplitude (C) across conditions ( N = 6 mice per group). P values are shown above comparisons. Large circles denote per-animal means; small circles indicate individual biological replicates. N represents the number of independent mice.

Article Snippet: For pharmacological experiments, ivabradine (30 μM; Tocris), thapsigargin (1 μM; Tocris), or RU360 (5 μM; Sigma-Aldrich) was added directly to the perfusate, and preparations were incubated for 30 min before recording line scans.

Techniques: Control, Inhibition, Fluorescence

Journal: The Journal of General Physiology

Article Title: Beat-locked ATP microdomains in the sinoatrial node map a Ca 2+ -timed energetic hierarchy and regional pacemaker roles

doi: 10.1085/jgp.202513874

Figure Lengend Snippet: Distinct mitochondrial redox regulation in the superior versus inferior SA node. (A) Representative FAD autofluorescence image of a mouse SA node illustrating spatial segregation of the superior (yellow outline) and inferior (white outline) regions. Scale bar, 50 µm. (B and C) Quantification of normalized FAD autofluorescence (F/F 0 ) in the superior (B) and inferior (C) SA node under control conditions and following I f inhibition with ivabradine (30 µM), SERCA inhibition with thapsigargin (1 µM), or mitochondrial uncoupling with FCCP (1 µM). The dashed line indicates baseline fluorescence (F/F 0 = 1). P values are shown above comparisons. P values indicate comparisons relative to baseline (F/F 0 = 1). Data are presented as means ± SEM ( N = 4 mice). Large circles denote per-animal means; small circles indicate individual biological replicates. N represents the number of independent mice.

Article Snippet: For pharmacological experiments, ivabradine (30 μM; Tocris), thapsigargin (1 μM; Tocris), or RU360 (5 μM; Sigma-Aldrich) was added directly to the perfusate, and preparations were incubated for 30 min before recording line scans.

Techniques: Control, Inhibition, Fluorescence