November 1, 1994Cardiovascular Research
Modulation of myocardial relaxation by basal release of endothelin from endocardial endothelium
Key result
Exposure to BQ123 in endocardium-intact ferret papillary muscles induced an earlier onset of isometric twitch relaxation (time to peak tension -12.3%, relaxation half time -13.3%; p<0.01).
Why the study?
Does basal endothelin-1 release from endocardial endothelium modulate myocardial relaxation in isolated ferret papillary muscles?
Population
Isolated ferret papillary muscle preparations (n=30 total, 5 groups of n=6)
Comparison
Endothelin-1, ETA receptor antagonist BQ123, and… vs No treatment (time control)
Design
Preclinical
Authors
Discussion
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Member takes
Implication
Supports tonic ET-1 modulation of relaxation in isolated muscle; leaves open relevance to intact hearts or human disease.
Structured PICO
Does basal endothelin-1 release from endocardial endothelium modulate myocardial relaxation in isolated ferret papillary muscles?
P
Population
30 isolated ferret papillary muscle preparations studied to evaluate the role of basal endothelin-1 release from endocardial endothelium.
I
Intervention
Endothelin-1 (5 nM), ETA receptor antagonist BQ123 (10 microM), and endocardial denudation
C
Comparator
No treatment (time control)
O
Outcome
Isometric twitch relaxation parameters (time to peak tension, relaxation half time, peak tension, rate of tension development)surrogate
Main Result
p-value: p=<0.01
Basal release of endothelin-1 from the endocardial endothelium tonically delays the onset of myocardial relaxation, suggesting a physiological role in modulating contractile behavior.
Cite This Study
Evans et al. (1994) studied Myocardial relaxation (n=30). BQ123 (ETA receptor antagonist) vs. No treatment (time control) was evaluated on Isometric twitch relaxation (time to peak tension and relaxation half time) (p=<0.01). Exposure to BQ123 in endocardium-intact ferret papillary muscles induced an earlier onset of isometric twitch relaxation (time to peak tension -12.3%, relaxation half time -13.3%; p<0.01).