The overall long term objectives of the studies proposed in this application are to identify and to understand the ionic mechanisms that underlie the abnormalities in the transmembrane potentials of the subendocardial Purkinje cells that survive in the infarcted heart. It has been suggested that one or more of these electrophysiologic abnormalities may lead to the serious ventricular arrhythmias known to occur after infarction. Therefore, by more clearly defining and understanding the mechanisms for these electrophysiologic changes, we will provide information that may lead to the development of effective therapeutic interventions needed in this clinical setting. We will disaggregate single Purkinje cells from the subendocardium. Then, by using a variety of techniques we can determine the underlying basis for the electrical abnormalities. Transmembrane potential recordings and voltage clamp techniques will be used to identify whether there is a lesion in the availability of the Na+ current in the cells dispersed from the infarcted heart. Patch pipettes will be used to voltage clamp and identify whether there is a lesion in the Ca++ currents, inward rectifying, the delayed rectifier or the transient outward currents in these cells. In addition, in a series of microinjection of compounds that are known to alter action potential repolarization. In parallel, we will determine during voltage clamp protocols of the delayed rectifier and Ca++ currents, whether inclusion of these compounds restores the diseased depressed ionic current(s).

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL034477-06
Application #
3347410
Study Section
Cardiovascular and Renal Study Section (CVB)
Project Start
1985-07-01
Project End
1993-07-31
Budget Start
1992-08-01
Budget End
1993-07-31
Support Year
6
Fiscal Year
1992
Total Cost
Indirect Cost
Name
Columbia University (N.Y.)
Department
Type
Schools of Medicine
DUNS #
064931884
City
New York
State
NY
Country
United States
Zip Code
10027
Pinto, J M; Boyden, P A (1998) Reduced inward rectifying and increased E-4031-sensitive K+ current density in arrhythmogenic subendocardial purkinje myocytes from the infarcted heart. J Cardiovasc Electrophysiol 9:299-311
Aggarwal, R; Boyden, P A (1996) Altered pharmacologic responsiveness of reduced L-type calcium currents in myocytes surviving in the infarcted heart. J Cardiovasc Electrophysiol 7:20-35
Boyden, P A (1996) Cellular electrophysiologic basis of cardiac arrhythmias. Am J Cardiol 78:4-11
Jeck, C; Pinto, J; Boyden, P (1995) Transient outward currents in subendocardial Purkinje myocytes surviving in the infarcted heart. Circulation 92:465-73
Boyden, P A (1995) Animal models of atrial flutter. J Interv Cardiol 8:687-96
Boyden, P A (1995) Models of atrial reentry. J Cardiovasc Electrophysiol 6:313-24
Steinberg, S F; Zhang, H; Pak, E et al. (1995) Characteristics of the beta-adrenergic receptor complex in the epicardial border zone of the 5-day infarcted canine heart. Circulation 91:2824-33
Aggarwal, R; Boyden, P A (1995) Diminished Ca2+ and Ba2+ currents in myocytes surviving in the epicardial border zone of the 5-day infarcted canine heart. Circ Res 77:1180-91
Boyden, P A; Pinto, J M (1994) Reduced calcium currents in subendocardial Purkinje myocytes that survive in the 24- and 48-hour infarcted heart. Circulation 89:2747-59
Tseng, G N; Boyden, P A (1991) Different effects of intracellular Ca and protein kinase C on cardiac T and L Ca currents. Am J Physiol 261:H364-79

Showing the most recent 10 out of 14 publications