Abstract
The mechanism that links membrane potential changes to the release
of calcium from internal stores to cause contraction of cardiac cells
is unclear. By using the calcium indicator fura-2 under voltage-clamp
conditions, changes in intracellular calcium could be monitored in
single rat ventricular cells while controlling membrane potential.
The voltage dependence of the depolarization-induced increase in
intracellular calcium was not the same as that of the calcium current
(Isi), which suggests that only a small fraction of Isi is required
to trigger calcium release from the sarcoplasmic reticulum. In addition,
sarcoplasmic reticulum calcium release may be partly regulated by
membrane potential, since repolarization could terminate the rise
in intracellular calcium. Thus, changes in the action potential will
have immediate effects on the time course of the calcium transient
beyond those associated with its effects on Isi.
- 2446391
- animals,
- calcium,
- channels,
- gov't,
- heart,
- ion
- membrane
- myocardium,
- non-,
- p.h.s.,
- potentials,
- rats,
- research
- support,
- u.s.
Users
Please
log in to take part in the discussion (add own reviews or comments).