Calcium Kinetics
Figure 1: A representative tracing of extra-mitochondrial calcium kinetics following the addition of 60 μM Ca2+ into a solution containing isolated cardiac mitochondria and the calcium-sensitive marker APIII. The absorbance (AU) increased rapidly with the addition of Ca2+ (solid arrow), followed by a decline representing uptake of calcium by mitochondria. The slope and magnitude of this decline was quantified as calcium uptake rate and amount. Following mitochondrial loading with calcium, an increase in AU reflected calcium release by mitochondria (dashed arrow). Calcium release was quantified as the slope of this line, and was partially inhibited by CsA. The lower trace (no hemin) shows rapid uptake of calcium and an absence of release following loading. The upper trace (hemin = 10 μM) illustrates a reduction in calcium loading as well as early release.


Keywords: calcium kinetics,  flowchart

Calcium Uptake - Calcium Amount
Figure 2: a) Net calcium uptake rate (AU/sec) and b) calcium amount (AU) during the initial transport of calcium into mitochondria (uptake in Figure 1) as a function of [hemin] (2.5–10 μM) in the absence and presence of CsA (n = 7). *p < 0.05 vs control.


Keywords: calcium,  flowchart

Calcium release
Figure 3: Rate of calcium release (AU/sec) from isolated mitochondria as indicated by an increase in APIII absorbance signal following calcium loading in the absence and presence of CsA under different hemin concentrations (n = 7). There was no calcium release under control conditions in the absence of hemin. Calcium release was significantly greater than control in all experiments using hemin 2.5–10 μM with or without CsA (p < 0.01). In addition, calcium release was greater without CsA than with CsA at hemin 5 and 10 μM (*p < 0.05).


Keywords: calcium,  flowchart

VDAC-PBR-ANT
Figure 4: Representative current traces of VDAC-PBR-ANT channel complex in lipid bilayers. Under control conditions, VDAC-PBR-ANT isolates exhibited characteristic changes in conductance with applied voltages (Section A). Following exposure to hemin 5–10 μM, there was gradual disappearance of conductance changes, resulting in complete channel closure after ~ 3 min (n = 7). The top trace depicts the voltage protocol used for the corresponding current.


Keywords: scheme,  VDAC-PBR-ANT

VDAC-PBR-ANT
Figure 5: Current amplitude histograms of a VDAC-PBR-ANT channel complex reconstituted in lipid bilayer as exposure to defined concentrations of hemin. A the holding potential of –40 mV (on trans), VDAC-PBR-ANT stayed more frequently at maximal open state. Addition of 2.5, 5 and 10 μM hemin in the cis chamber promoted reduced current amplitudes to a lower and eventually zero value.


Keywords: scheme,  VDAC-PBR-ANT