Table 1. Blockade degree (% Control) of the ICa and different calcium measurements.
(global and focal cytosolic Ca2+ transients ([Ca2+]T) measured using Fluo-4 AM for global, GCaMP6-FKBP for the focal RyR2 microdomains, and mito-GCaMP6 targeted to mitochondrial matrix to monitor its Ca2+ profiles) between both cell types (rapidly and slowly inactivating ICa cells) for the two different treatments (acidosis and hypoxia). Rapidly and slowly inactivating ICa cell plots (columns) were compared for interventions, acidosis and hypoxia (rows), using the nonparametric Mann-Whitney rank sum test. Non-significant differences (n.s.) or significant differences between both cell types (in the columns on the right): Data are means ± SE of the number of cells n and number of cultures N shown in parentheses.
| Treatment | Rapidly | Slowly | ||
|---|---|---|---|---|
| Ica | [Ca2+]T | ICa | [Ca2+]T | |
| GCaMP6-FKBP (Focal RyR2 μ-domains) | ||||
| Acidosis | 26.5 ± 6.1 (4, 4) | 36.8 ± 4.8 (4, 4) | 28.3 ± 7.5 (3, 3) n.s. | 38.5 ± 7.5 (3, 3) n.s. |
| Hypoxia | 15.8 ± 4.7 (4, 4) | 26.5 ± 6.3 (4, 4) | 34.7± 5.3 (5, 4)* | 42.0 ± 9.1 (5, 4) n.s. |
| Fluo-4 AM (Global cytosolic calcium transients) | ||||
| Acidosis | 32.5 ± 7.2 (5, 4) | 22.8 ± 1.6 (5, 4) | 31.8 ± 8.1 (4, 4) n.s. | 19.6 ± 2.5 (4, 4) n.s. |
| Hypoxia | 23.9 ± 6.7 (5, 4) | 17.1 ± 1.7 (5, 4) | 42.1± 7.7 (4, 4)* | 21.2 ± 3.1 (4, 4) n.s. |
| GCaMP6-Cytochrome Probe (Mitochondria calcium uptake) | ||||
| Acidosis | 29.0 ± 5.7 (3, 3) | 15.6 ± 5.0 (3, 3) | 30.9 ± 6.2 (3, 3) n.s. | 5.9 ± 6.2 (3, 3) n.s. |
| Hypoxia | 18.1 ± 4.5 (3, 2) | 31.9 ± 4.7 (3, 2) | 34.1 ± 3.6 (4, 3)* | 41.1 ± 6.6 (4, 3) n.s. |
P < 0.05, Mann-Whitney rank-sum test.