Dynamics of Mitochondrial Redox and Energy Networks: Insights from an Experimental–Computational Synergy - Systems Biology of Metabolic and Signaling Networks - page 112

Energecs

S E R C A V N a K A

V A

V p C M

a

ATPases

A D P m
A D P i
C a 2 +

Mitochondrial
energecs

N A D H

m

Mechanical

Force &
Ca 2+ transient

C a 2 +

i
F o r c e

Electrical

R

T

ECG

P

P

Q

S

Acon potenal

I N a
I K s
I K 1
I K p

Ionic fluxes

I C a
INaCa
Jrel

Time

Fig. 5.1 Temporal unfolding of electrical, mechanical, and energetic processes during a single
cardiomyocyte beat as computed by the Excitation-Contraction coupling Mitochondrial Energetic
(ECME) model. The depolarization and repolarization phases of the action potential (AP) take
place during the first 200 ms when the ECME model is stimulated every 2 s. This calculation
reveals the multiple temporal scales involved. The gray shaded area is meant to highlight
the earlier occurrence of electrical as compared with mechanical (contraction-relaxation) and
metabolic/energetic processes. Mitochondrial energy fuels the electrical and contractile machinery
of the heart cell on a slower time scale (few seconds) compared with the electrical processes
(milliseconds), which are followed by mechanical events associated with the force of contraction
and the Ca 2+ transient