Related Experiment Videos
Effects of propofol on contractile response and electrophysiological properties in single guinea-pig ventricular
T Shigemura1, N Hatakeyama, N Shibuya
1Department of Anaesthesiology, Toyama Medical and Pharmaceutical University, Faculty of Medicine, Japan.
Abstract:
Effects of propofol on contractile response, action potential, resting membrane potential and L-type voltage-dependent calcium channel current were examined in guinea-pig single cardiac myocyte. Propofol (10(-4) M) inhibited contractile response induced by electrical stimulation (83.6% of control, n = 5), but did not change the resting membrane potential. On the other hand, propofol reduced the overshoot of action potential (10(-4) M), and shortened the duration of action potential (10(-5) and 10(-4) M). Whole-cell voltage clamp experiment showed inhibition of L-type calcium channel current (ICa, 10(-5) M: 90.8+/-1.39, 10(-4) M: 83.4+/-1.53% of control, n = 5). In addition, propofol showed use-dependent block of ICa. It is concluded that negative inotropic effect of propofol is caused by suppression of action potential, and that inhibition of ICa plays a role in shortening of the duration of action potential.
Insights
Propofol, an anesthetic, reduces heart muscle contraction by altering action potentials and inhibiting calcium channels. This study clarifies propofol's cardiac electrophysiological effects.
Area of Science:
- Cardiology
- Anesthesiology
- Molecular Pharmacology
Background:
- Propofol is a widely used anesthetic agent.
- Its precise cardiac electrophysiological effects require further elucidation.
Purpose of the Study:
- To investigate the effects of propofol on cardiac myocyte function.
- To determine propofol's impact on action potentials and calcium channel currents.
Main Methods:
- Experiments were conducted on single guinea-pig cardiac myocytes.
- Measurements included contractile response, action potential characteristics, and L-type calcium channel current (ICa) using whole-cell voltage clamp.
Main Results:
- Propofol (10(-4) M) significantly inhibited electrical stimulation-induced contractile response.
- It reduced action potential overshoot and shortened action potential duration.
- Propofol inhibited ICa in a concentration-dependent and use-dependent manner.
Conclusions:
- The negative inotropic effect of propofol is attributed to action potential suppression.
- Inhibition of ICa contributes to the shortening of action potential duration by propofol.