Abstract
Summary: The effects of procainamide and lignocaine, in concentractions from 10-6 to 10-2mol·litre-1, on the Na influx and contraction frequency of cultured heart cells were studied. Both drugs produced a prompt, dose-dependent reduction in Na influx which was significant (P<0.0l) for all concentrations tested. Lignocaine affected only that portion of the Na influx which was also verapamil-sensitive, whereas procainamide suppressed in addition, the verapamil-insensitive influx. In addition both drugs produced a concomitant decrease in the spontaneous contraction frequency of the cells. A close linear correlation (r - 0.99) between verapamil-sensitive Na influx and contraction frequency, in the presence of both procainamide and lignocaine was found. From this, and previous studies indicating a dependency of contraction frequency on the inward verapamil-sensitive Na influx, it is suggested that the drugs modify the automaticity of this preparation by a primary influence on membrane Na exchange.
Original language | English (US) |
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Pages (from-to) | 529-536 |
Number of pages | 8 |
Journal | Cardiovascular Research |
Volume | 12 |
Issue number | 9 |
DOIs | |
State | Published - Sep 1978 |
ASJC Scopus subject areas
- Physiology
- Cardiology and Cardiovascular Medicine
- Physiology (medical)