Ryanodine receptor current amplitude controls Ca2+ sparks in cardiac muscle.

ABSTRACT:

Rationale

In cardiac muscle, Ca(2+)-induced Ca(2+) release (CICR) from the sarcoplasmic reticulum (SR) is mediated by ryanodine receptor (RyR) Ca(2+) release channels. The inherent positive feedback of CICR is normally well-controlled. Understanding this control mechanism is a priority because its malfunction has life-threatening consequences.

Objective

We show that CICR local control is governed by SR Ca(2+) load, largely because load determines the single RyR current amplitude that drives inter-RyR CICR.

Methods and results

We differentially manipulated single RyR Ca(2+) flux amplitude and SR Ca(2+) load in permeabilized ventricular myocytes as an endogenous cell biology model of the heart. Large RyR-permeable organic cations were used to interfere with Ca(2+) condu

SUBMITTER: Guo T 

PROVIDER: S-EPMC3417769 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature