Localization of Ca2+ release channels with ryanodine in junctional terminal cisternae of sarcoplasmic reticulum of fast skeletal muscle.

Abstract

The mechanism of Ca2' release from sarcoplasmic reticulum, which triggers contraction in skeletal muscle, remains the key unresolved problem in excitation-contraction coupling. Recently, we have described the isolation of purified fractions referable to terminal and longitudinal cisternae of sarcoplasmic reticulum. Junctional terminal cisternae are distinct in that they have a low net energized Ca2+ loading, which can be enhanced 5-fold or more by addition of ruthenium red. The loading rate, normalized for calcium pump protein content, then approaches that of longitudinal cisternae of sarcoplasmic reticulum. We now find that the ruthenium red-enhaniced Ca2+ loading rate can be blocked by the previous addition of ryanodine. The inhibition constant is in the nanomolar range (20-180 nM). Ryanodine and ruthenium red have no effect on the Ca21 loading rate of longitudinal cisternae. Direct binding studies with [3HJryano-dine localized the receptors to the terminal cisternae and not to longitudinal cisternae. Scatchard analysis of the binding data gives a dissociation constant for ryanodine in the range of the drug action on the terminal cisternae ("100 nM range) with approximately 4 to 20 pmol bound per mg of protein.Ryanodine is known to be toxic in animals, leading to irreversible muscle contractures. These studies provide evidence on the mode of action of ryanodine and its localization to the terminal cisternae. The low concentration at which the drug is effective appears to account for its toxicity. Ryanodine locks the Ca2+ release channels in the "open state," so that Ca2+ is not reaccumulated and the muscle fiber cannot relax.

High affinity ryanodine binding sites in rat liver endoplasmic reticulum

“…If as suggested, ryanodine is a Ca 2+ release channelspecific marker [3,6,19,20] then it should affect the Ca 2+ permeability of the liver microsomes. This was tested by determining the Ca z+ permeability of vesicles passively loaded with 45CaZ+ in the presence and absence of ryanodine.…”

“…These effects are due to the interaction of ryanodine with the SR, thereby modulating the Ca 2÷ release activity of this membrane [2,3]. Recent studies identified morphologically the purified ryanodine receptor with the 'foot' structure [4] and with the junctional Ca 2÷ release channel [5][6][7].…”

Ruthenium red and magnesium ion partially inhibit silver ion-induced release of calcium from sarcoplasmic reticulum of frog skeletal muscles.

“…Ryanodine receptor, which is located on the terminal cisternae of SR (FLEISCHER et al, 1985), has been purified (a single polypeptide of Mr 360,000) and shown to display Ca2 + channel activity with characteristics similar to the Ca2 +-induced Ca2 + release channel (FLEISCHER et al, 1985;HYMEL et al, 1988;LAI et al, 1988). Rapid Ca2 + release produced by either binding of heavy metals to or oxidation of sulfhydryl group on the SR membrane is strikingly similar to Ca2 +-induced Ca2 + release (SALAMA and ABRAMSON, 1984;TRIMM et al, 1986;MOUTIN and DUPONT, 1988;STUART and ABRAMSON, 1988;TATSUMI et al, 1988).…”

Caffeine causes glycerophosphorylcholine accumulation through ryanodine-inhibitable increase of cellular calcium and activation of phospholipase A2 in cultured MDCK cells

“…The following studies were aimed at defining which of the many pathways of caffeine action is involved. (Slivka and Insel, 1987;Gronich et al, 1990;Nakamura et al, 1991;Weiss and Insel, 1991), and millimolar concentrations of caffeine may increase [Ca 2 + ] i c o n c e n t r a t i o n both in muscular (Fleischer et al, 1985;Campbell et al, 1987;Iino et al, 1988) and non-muscular cells (Lipscombe et al ., 1988;Burgoyne et al ., 1989;Hernandez-Cruz et al, 1990;Malgaroli et al, 1990;Zacchetti et al, 1991). Caffeine mobilizes cellular Ca 2+ from intracellular stores by activating Ca 2 + channels that are sensitive to ryanodine.…”

“…It is well known that in a variety of cell types such as muscular cells (Fleischer et al, 1985;Campbell et al , 1987;Iino et al, 1988), neurons (Lipscombe et al, 1988;Hernandez-Cruz et al, 1990;Zacchetti et al, 1991), endocrine cells (Burgoyne et al, 1989;Malgaroli et al, 1990) and the pancreatic acinar cells (Wakui et al, 1990), caffeine increases the intracellular free calcium ([Ca 2+ ] i ) level through ryanodine, a neutral plant alkaloid, -sensitive or -insensitive Ca 2 + channel located in intracellular calcium stores. However, there is no informations about the action of caffeine and ryanodine on the cellular calcium change in renal epithelial cells.…”