The calcium-sensitive bioluminescent protein aequorin and related photoproteins will be used to study the regulation of intracellular Ca++ concentration in frog skeletal muscle, and in frog and mammalian cardiac muscle. Results will be compared in some circumstances with those obtained with calcium-selective micro- electrodes. High-gain microscopic image intensification with computer image processing will be used to localize Ca++ in aequorin-injected cells. A major effort will be mounted to resolve the isospecies of aequorin and other photoproteins, and to study their kinetics and Ca++-sensitivity. Particular emphasis in the studies on cardiac muscle will be given to the analysis of the role played by changes in myofibrillar responsiveness to Ca++ in responses of the heart to inotropic interventions, particularly the response to alpha-adrenoceptor stimulation. Systematic analysis will also be carried out of the factors responsible for alterations in the Ca++ transient after changes in muscle length and contraction frequency. In skeletal muscle a variety of experiments are planned to critically test the hypothesis that inositol triphosphate release is centrally involved in excitation:contraction coupling.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37HL012186-22
Application #
3485310
Study Section
Physiology Study Section (PHY)
Project Start
1977-04-01
Project End
1992-12-31
Budget Start
1991-01-01
Budget End
1991-12-31
Support Year
22
Fiscal Year
1991
Total Cost
Indirect Cost
Name
University of Washington
Department
Type
Schools of Medicine
DUNS #
135646524
City
Seattle
State
WA
Country
United States
Zip Code
98195
Illarionov, B A; Frank, L A; Illarionova, V A et al. (2000) Recombinant obelin: cloning and expression of cDNA purification, and characterization as a calcium indicator. Methods Enzymol 305:223-49
Klabusay, M; Blinks, J R (1996) Some commonly overlooked properties of calcium buffer systems: a simple method for detecting and correcting stoichiometric imbalance in CaEGTA stock solutions. Cell Calcium 20:227-34
Endoh, M (1994) The effects of theophylline on aequorin light transients and force in the isolated dog right ventricular myocardium. J Mol Cell Cardiol 26:87-98
Blatter, L A; Blinks, J R (1991) Simultaneous measurement of Ca2+ in muscle with Ca electrodes and aequorin. Diffusible cytoplasmic constituent reduces Ca(2+)-independent luminescence of aequorin. J Gen Physiol 98:1141-60
Endoh, M (1991) Physiological and pathophysiological modulation of calcium signaling in myocardial cells. Jpn Circ J 55:1108-17
Blatter, L A (1991) Estimation of intracellular free magnesium using ion-selective microelectrodes: evidence for an Na/Mg exchange mechanism in skeletal muscle. Magnes Trace Elem 10:67-79
Gwathmey, J K; Warren, S E; Briggs, G M et al. (1991) Diastolic dysfunction in hypertrophic cardiomyopathy. Effect on active force generation during systole. J Clin Invest 87:1023-31
Lab, M J; Lee, J A (1990) Changes in intracellular calcium during mechanical alternans in isolated ferret ventricular muscle. Circ Res 66:585-95
Blinks, J R (1990) Use of photoproteins as intracellular calcium indicators. Environ Health Perspect 84:75-81
Fry, C H; Hall, S K; Blatter, L A et al. (1990) Analysis and presentation of intracellular measurements obtained with ion-selective microelectrodes. Exp Physiol 75:187-98

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