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Effect of aminophylline on mechanical activity of rat diaphragm bundles | JoVE Visualize

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Effect of aminophylline on mechanical activity of rat diaphragm bundles

O Delbono¹, B A Kotsias

¹Instituto de Investigaciones Médicas, A. Lanari, Buenos Aires, Argentina.

Journal of Applied Physiology (Bethesda, Md. : 1985)|March 1, 1990

View abstract on PubMed

Summary

Aminophylline enhances muscle twitch tension by lowering the mechanical threshold in rat diaphragm fibers. This effect, related to calcium release, is reversible and blocked by nifedipine.

Area of Science:

Muscle physiology
Pharmacology

Background:

Aminophylline is a bronchodilator with potential effects on muscle function.
Understanding its impact on skeletal muscle is crucial for clinical applications.

Purpose of the Study:

To investigate the effects of aminophylline on the mechanical and electrical activity of rat diaphragm muscle.
To elucidate the mechanism underlying aminophylline-induced potentiation of muscle tension.

Main Methods:

In vitro study on isolated rat diaphragm bundles at 25°C.
Measurement of twitch and tetanus tensions, resting membrane potential, and mechanical threshold.
Application of aminophylline (0.1-1 mM) and nifedipine (1 μM).

Main Results:

Aminophylline potentiated twitch tension but did not alter tetanus tension.
A shift in the tension-membrane potential relationship and a lowered mechanical threshold were observed.
Effects were reversible and antagonized by nifedipine, suggesting a role for calcium release.

Conclusions:

Aminophylline potentiates diaphragm muscle tension primarily by lowering the mechanical threshold.
The mechanism involves enhanced calcium release from the sarcoplasmic reticulum, potentially blocked by nifedipine.

Mechanical Engineering

Numerical Modelling And Mechanical Characterisation

Effect Of Aminophylline On Mechanical Activity Of Rat Diaphragm Bundles