Аннотация
Excitation contraction (e-c) coupling in skeletal and cardiac muscles
involves an interaction between specialized junctional domains of
the sarcoplasmic reticulum (SR) and of exterior membranes (either
surface membrane or transverse (T) tubules). This interaction occurs
at special structures named calcium release units (CRUs). CRUs
contain two proteins essential to e-c coupling: dihydropyridine receptors
(DHPRs), L-type Ca$^2+$ channels of exterior membranes; and ryanodine
receptors (RyRs), the Ca$^2+$ release channels of the SR. Special
CRUs in cardiac muscle are constituted by SR domains bearing RyRs
that are not associated with exterior membranes (the corbular and
extended junctional SR or EjSR). Functional groupings of RyRs and
DHPRs within calcium release units have been named couplons, and
the term is also loosely applied to the EjSR of cardiac muscle. Knowledge
of the structure, geometry, and disposition of couplons is essential
to understand the mechanism of Ca$^2+$ release during muscle
activation. This paper presents a compilation of quantitative data
on couplons in a variety of skeletal and cardiac muscles, which is
useful in modeling calcium release events, both macroscopic and microscopic
("sparks").
- 10465763
- animals,
- calcium
- calcium,
- cell
- channel,
- channels,
- chickens,
- dogs,
- electron,
- fishes,
- fracturing,
- freeze
- gov't,
- guinea
- heart,
- in
- l-type,
- membrane,
- mice,
- microscopy,
- muscle,
- myocardium,
- p.h.s.,
- pigs,
- ranidae,
- rats,
- receptor
- release
- research
- reticulum,
- ryanodine
- sarcoplasmic
- skeletal,
- support,
- u.s.
- vitro,
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