Muscle sarcoplasmic reticulum

Site symmetry symbols, I, 128 Six-coordinate compounds stereochemistry, 1, 49-69 Six-membered rings metal complexes, 2, 79 Skeletal muscle sarcoplasmic reticulum calcium pump, 6, 565 Slags... 

Rousseau, E., LaDine, J., Liu, Q.-Y., Meissner, G. (1988). Activation of the Ca release channel of skeletal muscle sarcoplasmic reticulum by caffeine and related compounds. Arch. Biochem. Biophys. 267, 75-86. 

Smith, J.S., Coronado, R., Meissner, G. (1986). Single channel measurements of the calcium release charmel from skeletal muscle sarcoplasmic reticulum. J. Gen. Physiol. 88, 573-588. 

Harioka, T., Sone, T., Toda, H. (1990). Ca release channel (ryanodine receptor) of skeletal muscle sarcoplasmic reticulum. J. Biol. Chem. 265, 2244-2256. 

The cDNA clone for the neonatal rabbit fast-twitch skeletal muscle Ca -ATPase encodes for 1001 amino acids giving a product with an estimated molecular weight of 110 331 Da [8], The clone for the Ca -ATPase of slow-twitch skeletal muscle sarcoplasmic reticulum (S-Ca -ATPase) encoded for 997 amino acids with a relative molecular mass (Mr) of 109 529 kDa [42],... 

Second-line Dantrolene Direct inhibitor of muscle contraction by decreasing the release of calcium from skeletal muscle sarcoplasmic reticulum 25 mg orally daily, increase to 25 mg 3-4 times daily, then increase by 25 mg every 4-7 days to a maximum of 400 mg/day... 

Louis, C.F., Saunders, M.J., and Holroyd, J.A. (1977) The cross-linking of rabbit skeletal muscle sarcoplasmic reticulum protein. Biochim. Biophys. Acta 493, 78-92. 

Odermatt, A., Taschner, P. E., Khanna, V. K. etal. Mutations in the gene-encoding SERCA1, the fast-twitch skeletal muscle sarcoplasmic reticulum Ca2+ ATPase, are associated with Brody disease. Nat. Genet.lA. 191-194,1996. 

Turner WH, Brading AF 1997 Smooth muscle of the bladder in the normal and the diseased state pathophysiology, diagnosis and treatment. Pharmacol Ther 75 77—110 van Breemen C, Chen Q, Laher I 1995 Superficial buffer barrier function of smooth muscle sarcoplasmic reticulum. Trends Pharmacol Sci 16 98-105 Wray S 1993 Uterine contraction and physiological mechanisms of modulation. Am J Physiol 264 C1-C18... 

Carafoli E, Santella L, Branca D, Brini M 2001 Generation, control, and processing of cellular calcium signals. Crit Rev Biochem Mol Biol 36 107—260 Chen Q, van Breemen C 1993 The superficial buffer barrier in venous smooth muscle sarcoplasmic reticulum refilling and unloading. Br J Pharmacol 109 336—343 Clapham DE, Runnels LW, Strubing C 2001 The TRP ion channel family. Nat Rev Neurosci 2 387-396... 

Mercuric chloride is thought to gain access to the intracellular compartment through Na + and Ca2 + channels in the membrane [ 100]. Sulphydryl reagents, including Hg2 +, could inhibit K +-stimulated uptake of Ca2+ into rat brain synaptosomes in vitro [101]. In muscle sarcoplasmic reticulum, Hg2+ causes inhibition of ATP-dependent Ca2 + uptake and loss of accumulated calcium [ 102,103]. However, HgCl2 has been found to inhibit ATP-dependent calcium uptake more strongly than it inhibits potassium-stimulated uptake [ 104],... 

Eukaryotic cell plasma membranes Muscle sarcoplasmic reticulum Eukaryotic cell plasma membranes Stomach epithelial cell plasma membranes... 

Chu, A., Fill, M., Stefani, E., and Entman, M. L. (1993). Cytoplasmic Ca2+ Does not Inhibit the Cardiac Muscle Sarcoplasmic Reticulum Ryanodine Receptor Ca2+ Channel, Although Ca(2+)-induced Ca2+ Inactivation of Ca2+ Release is Observed in Native Vesicles. J Membr Biol 135(1) 49—59. 

Zhang, Y., Fujii, J., Phillips, M. S., Chen, H. S., Karpati, G., Yee, W. C., Schrank, B., Cornblath, D. R., Boylan, K. B., and MacLennan, D. H., 1995, Characterization of cDNA and genomic DNA encoding SERCA 1, the Ca(2+)-ATPase of human fast-twitch skeletal muscle sarcoplasmic reticulum, and its elimination as a candidate gene for Brody disease. Genomics, 30 415-24. 

MacLennan, D.H., Brandi, C.J., Korczak, B., Green, N.M. (1985). Amino-add sequence of a Ca2+ + Mg2+-dependent ATPase from rabbit muscle sarcoplasmic reticulum, deduced from its complementary DNA sequence. Nature (London) 316,696-700. 

Radicals generated during peroxidation of lipids and proteins show reactivity similar to that of the hydroxyl radical however, their oxidative potentials are lower. It is assumed that the reactive alkoxyl radicals rather than the peroxyl radicals play a part in protein fragmentation secondary to lipid peroxidation process, or protein exposure to organic hydroperoxides (DIO). Reaction of lipid radicals produces protein-lipid covalent bonds and dityrosyl cross-links. Such cross-links were, for example, found in dimerization of Ca2+-ATPase from skeletal muscle sarcoplasmic reticulum. The reaction was carried out in vitro by treatment of sarcoplasmic reticulum membranes with an azo-initiator, 2,2/-azobis(2-amidinopropane) dihydrochloride (AAPH), which generated peroxyl and alkoxyl radicals (V9). 

The effect of change in ionic radius in going from La3+ to Lu3+ showed in some cases no systematic trend. While in other cases two types of trend have been observed (i) systematic increase from La3+ to Lu3+ for the activation of a-amylase [10], (ii) decrease in effect from La3+ to Lu3+ in the case of inhibition of Ca2+/Mg2+-ATPase of skeletal muscle sarcoplasmic reticulum [11],... 

Meissner G. Ionic permeability of isolated muscle sarcoplasmic reticulum and liver endoplasmic reticulum vesicles. Methods En-zymol. 1988 157 417-437. 

Ehrlich, B.E. and Watras, J. (1988). Inositol 1,4,5-trisphosphate activates a channel from smooth muscle sarcoplasmic reticulum. Nature 336, 583-586. 

The Ca -ATPase piays an essential role In the pumping of calcium out of cells, and in the control of its cytosolic concentration. In the heart, the role of the pump is minor with respect to that of the sodium-calcium exchanger, but is most probabiy predominant in skeletal and smooth muscle. The pump is encoded by four independent genes, showing different patterns of tissue-specific expression and alternative splicing of the primary transcripts. The intracellular Ca pump proteins from skeletal muscle sarcoplasmic reticulum (SR), cardiac SR and brain microsomes are similar. Thapsigargin is a potent inhibitor, also lanthanum salts inhibit the pump at most sites. 

The answer is c. (Murray, pp 238-249. Scriver, pp 2367-2424. Sack, pp 159-175. Wilson, pp 287-317.) A variety of agonists activate the plasma membrane-bound enzyme phospholipase C, which hydrolyzes the phosphodiester bond of phosphatidyl inositol 4,5-bisphosphate and consequently releases diacylglycerol (DAG) and inositol 1,4,5-triphosphate (IP3). Phospholipase C is also known as phosphoinositidase and as polyphosphoinositide phosphodiesterase. Both DAG and IP3 are second messengers. DAG activates protein kinase C, which is important in controlling cell division and cell proliferation. IP3 opens calcium channels and allows the rapid release of the calcium stores in endoplasmic reticulum (in smooth muscle, sarcoplasmic reticulum). The elevated levels of calcium ion stimulate smooth-muscle contraction, exocytosis, and glycogen breakdown. 

Hyperthermia is a rare complication of anesthesia that is not completely understood. Most of the evidence points to the ryanodine receptor (chromosome 19ql3.1) as the defective gene product. This receptor is the Ca release channel of muscle sarcoplasmic reticulum. Stimulation of this channel leads to excessive Ca release from the cisternae of the sarcoplasmic reticulum, and that Ca prompts muscle contraction, an increase in body temperature, tachycardia, and subsequent metabolic acidosis. 

Spasmolytics reduce excess muscle tone or spasm in injury or CNS dysfunction. They may act in the CNS, the spinal cord, or directly on the muscle. Benzodiazepines and baclofen reduce the tonic output of spinal motor neurons. Dantrolene blocks Ca2 release from the muscle sarcoplasm reticulum. 

Although suppression of the voltage-activated inward displacement of Ca + is undoubtedly the most widely discussed property of the substances listed in Table I, some of these drugs exhibit other properties that may be of clinical relevance. For example verapamil (61,62) and nifedipine bind to a receptors in brain, neurobiastomaglioma hybrid (63) and cardiac muscle cells (64). Verapamil and methoxyverapamil also bind fairly tightly to muscarinic receptors (65). Verapamil and D-600 have an inhibitory effect on Na+ and K" conductance, (23,63) an effect which apparently is not shared by nifedipine. Diltiazem slows the release of Ca + from smooth muscle sarcoplasmic reticulum (66). 

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