What question did this study set out to answer?

To investigate the cellular mechanisms responsible for the cardiotoxic, negative inotropic effects exerted by various opioids on myocardium.

March 1, 1997Experimental Physiology

The mode of action of several opioids on cardiac muscle

View Full Paper

Ask AI

Bookmark

To investigate the cellular mechanisms responsible for the cardiotoxic, negative inotropic effects exerted by various opioids on myocardium.
Measured myocardial twitch tension, intracellular Ca2+ transients, and L-type Ca2+ currents (ICa) in response to opioids, including dextropropoxyphene and pethidine.
Evaluated action potential characteristics, intracellular pH, receptor involvement using the antagonist naloxone, and correlation with the oil-water partition coefficient.
Opioids produced negative inotropic effects with half-maximal concentrations between 10 µM (dextropropoxyphene) and 118 µM (pethidine), matching reductions in intracellular Ca2+ transients and ICa.
Depression of ICa correlated positively with the oil-water partition coefficient and was not reversed by naloxone.
Action potential upstroke rate was reduced only at significantly higher concentrations, while resting potential, action potential duration, and intracellular pH were unchanged.

Structured PICO

Population

Cardiac muscle (myocardium) in a preclinical model

Intervention

Several opioids (including dextropropoxyphene and pethidine)

Outcome

Inotropic effect (twitch tension), intracellular Ca2+ transient, and L-type Ca2+ current (ICa)surrogate

Opioids exert a negative inotropic effect on cardiac muscle by depressing the L-type Ca2+ current in a non-specific, hydrophobicity-dependent manner independent of opioid receptors.

Discussion

No takes yet. Share an insight, caveat, or question.

Implication

Opioids may depress contractility via non-receptor Ca2+ effects at high doses; leaves open clinical relevance in intact human myocardium.

Cite This Study

Wu et al. (1997) studied this question.

synapsesocial.com/papers/6a853cc9abe7e878c1964ec2 https://doi.org/10.1113/expphysiol.1997.sp004021

View Full Paper

Ask AI

Bookmark

The mode of action of several opioids on cardiac muscle

Key Points

Structured PICO

Discussion

Implication

Cite This Study

The mode of action of several opioids on cardiac muscle

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Also Consider

Also Consider