The objective of the research is to define the chemical structure and the biological properties of an endogenous inhibitor of the (Na-K) pump present in human cerebrospinal fluid (CSF). This proposal stems from our observation that a component of human CSF inhibits the active transport of cations in human red cells and the in vitro activity of the enzyme (Na-K) ATPase. This inhibitory substance, possibly a neuropeptide, can be separated by chromatographic techniques, is sensitive to proteolytic digestion and increases after the expansion of the extracellular fluid volume.
Specific aims i nclude: 1) Purification and identification of the (Na-K) pump inhibitor of human CSF; 2) Sequence and synthesis of the active molecule(s); 3) Investigation of the mechanism underlying its inhibitory action on the (Na-K) ATPase; 4) Studies on its biological properties; and 5) Development of specific and sensitive tests allowing its detection in body fluids and tissues. These studies should provide new information about the physiological regulation of ion transport across cell membranes. In addition, they may also provide new insights, and possibly new biological tests and pharmacological approaches, to the pathophysiology of ion transport and related diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
1R01NS023367-01
Application #
3406756
Study Section
Neurological Sciences Subcommittee 1 (NLS)
Project Start
1986-09-01
Project End
1989-08-31
Budget Start
1986-09-01
Budget End
1987-08-31
Support Year
1
Fiscal Year
1986
Total Cost
Indirect Cost
Name
Harvard University
Department
Type
Schools of Medicine
DUNS #
082359691
City
Boston
State
MA
Country
United States
Zip Code
02115
Halperin, J A (1989) Digitalis-like properties of an inhibitor of the Na+/K+ pump in human cerebrospinal fluid. J Neurol Sci 90:217-30
Lorenzo, A V; Taratuska, A; Halperin, J A (1989) Suppression of cerebrospinal fluid (CSF) production by a Na+/K+ pump inhibitor extracted from human cerebrospinal fluid. Z Kinderchir 44 Suppl 1:24-6
Halperin, J A; Brugnara, C; Nicholson-Weller, A (1989) Ca2+-activated K+ efflux limits complement-mediated lysis of human erythrocytes. J Clin Invest 83:1466-71
Halperin, J A; Nicholson-Weller, A (1989) Paroxysmal nocturnal hemoglobinuria. A complement-mediated disease. Complement Inflamm 6:65-72
Nicholson-Weller, A; Halperin, J A (1989) Mechanisms by which the erythrocyte protects itself from complement damage. Prog Clin Biol Res 297:263-70;discussion 270-1
Halperin, J A; Nicholson-Weller, A; Brugnara, C et al. (1988) Complement induces a transient increase in membrane permeability in unlysed erythrocytes. J Clin Invest 82:594-600
Halperin, J A; Brugnara, C; Kopin, A S et al. (1987) Properties of the Na+-K+ pump in human red cells with increased number of pump sites. J Clin Invest 80:128-37
Halperin, J A; Lobb, R R (1987) Effect of heparin-binding growth factors on monovalent cation transport in Balb/C 3T3 cells. Biochem Biophys Res Commun 144:115-22