Every cell is surrounded by a plasma membrane that divides cytoplasm from extracellular fluid and separates one cell from another. The membrane and membrane-associated components play vital roles in virtually every aspect of cell function. During embryonic development, the differentiation of a variety of histotypic cell properties is associated with gentically controlled alterations in surface-associated molecules such as receptors for hormones and neurotransmitters, transport proteins and ion conductance channels. It is the goal of this Program to understand how certain specific components of the cell membrane and the membrane-associated cytoskeleton serve as regulators of cell function, and how changes in these components with development result in the achievement of definitive functional states in excitable cells. By application of biochemical, biophysical, genetic, and ultrastructural techniques to cardiac cells in a number of in vitro model system, we hope to gain insight into the mechanisms underlying membrane function. The unifying theme of the Program is the role of cell surface components in regulating cell function. There are three major approaches. One effort focuses on specific ion conductance mechanisms in the heart cell membrane; how they develop in the embryonic heart, and what role they have in macroscopic and microscopic electrical activity. A second focus deals with receptor mechanisms for insulin and acetylcholine, and how these ligands activate currents and other cellular activities. The third area is the physiological and genetic regulation of ion transport mechanisms in the cell membrane. This is a renewal proposal for five years of support for an expanded effort by seven experienced investigators. The Program includes seven inter-related projects subserved by six core facilities.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
5P01HL027385-11
Application #
3097972
Study Section
Heart, Lung, and Blood Research Review Committee A (HLBA)
Project Start
1981-07-01
Project End
1994-06-30
Budget Start
1991-08-02
Budget End
1992-06-30
Support Year
11
Fiscal Year
1991
Total Cost
Indirect Cost
Name
Emory University
Department
Type
Schools of Medicine
DUNS #
042250712
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Chen, Y H; DeHaan, R L (1996) Asymmetric voltage dependence of embryonic cardiac gap junction channels. Am J Physiol 270:C276-85
Kumar, R; Joyner, R W (1995) Calcium currents of ventricular cell pairs during action potential conduction. Am J Physiol 268:H2476-86
Akita, T; Kumar, R; Joyner, R W (1995) Developmental changes in modulation of contractility of rabbit hearts. J Cardiovasc Pharmacol 25:240-51
Lu, C; Kumar, R; Akita, T et al. (1994) Developmental changes in the actions of phosphatase inhibitors on calcium current of rabbit heart cells. Pflugers Arch 427:389-98
Kumar, R; Joyner, R W; Hartzell, H C et al. (1994) Postnatal changes in the G-proteins, cyclic nucleotides and adenylyl cyclase activity in rabbit heart cells. J Mol Cell Cardiol 26:1537-50
Akita, T; Joyner, R W; Lu, C et al. (1994) Developmental changes in modulation of calcium currents of rabbit ventricular cells by phosphodiesterase inhibitors. Circulation 90:469-78
Galli, A; DeFelice, L J (1994) Inactivation of L-type Ca channels in embryonic chick ventricle cells: dependence on the cytoskeletal agents colchicine and taxol. Biophys J 67:2296-304
Kumar, R; Joyner, R W (1994) An experimental model of the production of early after depolarizations by injury current from an ischemic region. Pflugers Arch 428:425-32
Hartzell, H C; Duchatelle-Gourdon, I (1993) Regulation of the cardiac delayed rectifier K current by neurotransmitters and magnesium. Cardiovasc Drugs Ther 7 Suppl 3:547-54
Frace, A M; Mery, P F; Fischmeister, R et al. (1993) Rate-limiting steps in the beta-adrenergic stimulation of cardiac calcium current. J Gen Physiol 101:337-53

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