The Effect of Heterogeneously-distributed RyR Channels on Calcium Dynamics in Cardiac Myocytes

✍ Scribed by Peter A. Spiro

• Publisher: Springer
• Year: 1999
• Tongue: English
• Weight: 671 KB
• Volume: 61
• Category: Article
• ISSN: 1522-9602
• DOI: 10.1006/bulm.1999.0101

✦ Synopsis

Calcium plays an essential role in excitation-contraction coupling in muscle, and derangements in calcium handling can produce a variety of potentially harmful conditions, especially in cardiac muscle. In cardiac tissue specialized invaginations of the sarcolemma, called T-tubules, penetrate deep into each sarcomere, and depolarization of the SL leads to an influx of calcium through voltage-sensitive channels in the T-tubules that in turn triggers further calcium release from the sarcoplasmic reticulum via ryanodine-sensitive calcium channels. Under certain conditions, such as elevated external Ca 2+ , cardiac cells can release calcium from the sarcoplasmic reticulum spontaneously, producing a calcium 'spark' and propagating traveling waves of elevated Ca 2+ concentration, without depolarization of the SL