Korean J Anesthesiol.  1997 Feb;32(2):185-191. 10.4097/kjae.1997.32.2.185.

The Relaxant Effects of Propofol and Ketamine on Guinea-pig Tracheal Smooth Muscle

• Kim KJ
• Koh SO
• Kim WO
• Nam YT

• KMID: 2240300
• DOI: http://doi.org/10.4097/kjae.1997.32.2.185

Abstract

BACKGROUND
Propofol inhibits postoperative bronchospasm. Ketamine prevents bronchospasm in asthmatic patients. The present study was designed to evaluate the effects and mechanisms of propofol and ketamine on tracheal smooth muscles.
METHODS
After isolating guinea-pig tracheal preparations, the maximal tracheal tones were induced by smooth muscle constrictors(2 10 7 M carbachol, 10 5 M histamine, 30 mM K+ Krebs solution, 124 mM K+ Krebs solution). When tracheal tones stabilized, propofol or ketamine was added cumulatively to obtain the concentration-relaxation curves, and calculated the ED50 and ED95.
RESULTS
Propofol and ketamine decreased maximal tracheal tones in the concentration-dependent manners. The ED50 and ED95 of propofol were lowest in the histamine group, highest in the 30 mM K+ Krebs solution group. The ED50 and ED95 of ketamine were lowest in the 124 mM K+ Krebs solution group, highest in the histamine group.
CONCLUSIONS
The relaxant effects of propofol and ketamine involve with all receptors in nonspecific way. However, propofol may inhibit more strongly the histamine mediated mechanism of tracheal contraction and ketamine may involve more strongly with Ca++ channel.

Keyword

Airway tracheal tone; intravenous ketamine; propofol; guinea-pig; smooth muscle

MeSH Terms

Bronchial Spasm
Carbachol
Histamine
Humans
Ketamine*
Muscle, Smooth*
Propofol*
Carbachol
Histamine
Ketamine
Propofol