The ryanodine receptor (RyR) in aortic and vas deferens smooth muscle was localized using immunofluorescence confocal microscopy and immunoelectron microscopy. Indirect immunofluorescent labeling of aortic smooth muscle with anti-RyR antibodies showed a patchy network-like staining pattern throughout the cell cytoplasm, excluding nuclei, in aortic smooth muscle and localized predominantly to th...

Ca2+-induced Ca2+ release (CICR) from the sarcoplasmic reticulum (SR) via ryanodine receptors (RyRs) ultimately governs cardiac muscle force and can be considered as an amplification system for cardiac Ca2+ signals. CICR is initiated by Ca2+ influx via voltagedependent L-type Ca2+ channels. Unlike skeletal muscle fibres, each cardiac myocyte can produce an amount of force (and a Ca2+ transient)...

The functional heterogeneity of the ryanodine receptor (RyR) channels in avian cerebellum was defined. Heavy endoplasmic reticulum microsomes had significant levels of ryanodine and inositol 1,4,5-trisphosphate binding. Scatchard analysis and kinetic studies indicated the existence of at least two distinct ryanodine binding sites. Ryanodine binding was calcium-dependent but was not significantl...

The proposal of adaptation in individual ryanodine receptor (RyR)/Ca 2 1 release channels (Györke and Fill, 1993) has been an exciting concept that has stimulated widespread consideration of the properties and mechanisms involved in the activation and termination of Ca 2 1 release in muscle and other cells. Here, we consider what adaptation of individual RyRs is defined to mean and examine the ...

The goal of this study was to examine the transmural distribution of ryanodine receptors in left ventricular (LV) hypertrophy (LVH) and its in vivo consequences. Dogs were chronically instrumented with an LV pressure gauge, ultrasonic crystals for measurement of LV internal diameter and wall thickness, and a left circumflex coronary blood flow velocity transducer. Severe LVH was induced by chro...

Heart mitochondria utilize multiple Ca(2+) transport mechanisms. Among them, the mitochondrial ryanodine receptor provides a fast Ca(2+) uptake pathway across the inner membrane to control "excitation and metabolism coupling." In the present study, we identified a novel ryanodine-sensitive channel in the native inner membrane of heart mitochondria and characterized its pharmacological and bioph...

signal activates specialized Ca 2 1 release channels, the ryanodine receptors (RyRs), in the sarcoplasmic reticulum (SR). This process is called Ca 2 1 -induced Ca 2 1 release (CICR). Intuitively, the CICR process should be self-regenerating because the Ca 2 1 released from the SR should feedback and activate further SR Ca 2 1 release. However, the CICR process is precisely controlled in the he...