Several putative roles for ryanodine receptors (RyR) were investigated in human and bovine airway smooth muscle. Changes in intracellular Ca concentration ([Ca]i) and membrane current were investigated in single cells by confocal fluorimetry and patch-clamp electrophysiology, respectively, whereas mechanical activity was monitored in intact strips with force transducers. RyR released Ca from th...

Phosphorylation of the rat brain ryanodine receptor was studied using a monoclonal antibody, Ry-1, against the cardiac ryanodine receptor. A large polypeptide with the same SDS-PAGE mobility as that of the canine cardiac receptor was detected in rat brain membranes by immunoblotting. The brain ryanodine receptor was solubilized from the microsomal membranes with 3-[(3-cholamidopropyl)dimethylam...

Striated muscle contraction is elicited by the release of stored calcium ions through ryanodine receptor channels in the sarcoplasmic reticulum. ryr-1 is a C. elegans ryanodine receptor homologue that is expressed in body-wall muscle cells used for locomotion. Using genetic methods, we show that ryr-1 is the previously identified locus unc-68. First, transposon-induced deletions within ryr-1 ar...

Interstitial cells of Cajal (ICC) provide pacemaker activity in gastrointestinal muscles that underlies segmental and peristaltic contractions. ICC generate electrical slow waves that are due to large-amplitude inward currents resulting from anoctamin 1 (ANO1) channels, which are Ca(2+)-activated Cl(-) channels. We investigated the hypothesis that the Ca(2+) responsible for the stochastic activ...

The inhibition by ryanodine of caffeine induced calcium release from actively loaded heavy sarcoplasmic vesicles has been studied in order to analyse the relation between the occupancy of the vesicular calcium release channels by ryanodine and channel function. Ryanodine binding was monitored with [3H]ryanodine under ionic conditions favouring the establishment of binding equilibrium. Binding f...