December 1, 1991Canadian Journal of Physiology and Pharmacology
α1-Adrenergic stimulation increases the Vmax of isolated myocardial papillary muscles
Population
Isolated myocardial papillary muscles from dogs and rabbits
Comparison
Phenylephrine in the presence of propranolol vs Increased extracellular calcium concentration
Design
Preclinical
Authors
Discussion
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Member takes
Implication
α1-stimulation augments rabbit myocardial contractility unevenly; hypothesis-generating for species differences, leaves open human translation.
Structured PICO
P
Population
Isolated myocardial papillary muscles from dogs and rabbits
I
Intervention
Phenylephrine (starting at 10^-8 M) in the presence of propranolol
C
Comparator
Increased extracellular calcium concentration (from 1.25 to 15 mM)
O
Outcome
Maximum velocity of unloaded muscle shortening (Vmax), tension, and maximum rate of tension developed (dT/dt)surrogate
α1-adrenergic stimulation increases all indices of myocardial contractility, though it increases Vmax relatively less than tension, with notable species differences between dogs and rabbits.
Cite This Study
Li et al. (1991) studied this question.