February 6, 1959
View Full PaperRelease of Autonomic Mediators in Cardiac Tissue by Suprathreshold Stimulation
Structured PICO
Does suprathreshold stimulation increase contractile strength via the release of an adrenergic mediator in isolated cardiac muscle?
P
Population
isolated cardiac muscle
I
Intervention
suprathreshold stimulation
C
Comparator
stimulation at threshold levels
O
Outcome
contractile strengthsurrogate
Suprathreshold stimulation increases contractile strength in isolated cardiac muscle via the release of norepinephrine.
Abstract
Pharmacological evidence is presented supporting the theory that the increase in contractile strength of isolated cardiac muscle under suprathreshold stimulation is due to the release of an adrenergic mediator (norepinephrine). However, release of this material does not account for changes in contractile strength associated with changes in frequency of stimulation at threshold levels.