Smooth muscle relaxant effects of propofol and ketamine in isolated guinea-pig trachea

• Published in: European journal of pharmacology Vol. 238; no. 1; pp. 75 - 80
• Main Authors: Pedersen, Charles M., Thirstrup, Steffen, Nielsen-Kudsk, Jens Erik
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 06.07.1993; Elsevier
• Subjects: Anaesthetics; Anesthetics. Neuromuscular blocking agents; Animals; Asthma; Biological and medical sciences; Carbachol - pharmacology; Dinoprost - pharmacology; Dose-Response Relationship, Drug; Female; Guinea Pigs; Histamine - pharmacology; In Vitro Techniques; Ketamine; Ketamine - pharmacology; Male; Medical sciences; Muscle Relaxation - drug effects; Muscle, Smooth - drug effects; Muscle, Smooth - physiology; Neuropharmacology; Pharmacology. Drug treatments; Potassium - pharmacology; Propofol; Propofol - pharmacology; Smooth muscle; Trachea; Trachea - drug effects; Trachea - physiology; Smooth muscle; Ketamine; Propofol; Trachea; Asthma; Anaesthetics; Bronchodilation; Intravenous administration; Rodentia; In vitro; Muscular relaxation; Respiratory tract; Vertebrata; Mammalia; Guinea pig; General anesthetic; Animal; Comparative study
• ISSN: 0014-2999; 1879-0712
• DOI: 10.1016/0014-2999(93)90507-E

The effects of anesthetics on airway smooth muscle tone are important in the management of patients with asthma. In the present study we evaluated the effect of propofol and ketamine on isolated guinea-pig tracheal preparations mounted for recording isometric contractile force. In a concentration-dependent way both drugs produced 100% relaxation irrespective of whether tracheal tone was spontaneous or induced by carbachol, histamine, prostaglandin F 2α, 30 mM K + or 124 mM K +. The relaxant potency of propofol was dependent of the formulation of the drug used. Propofol showed an about 3 times higher potency when solubilized with hydroxypropyl-β-cyclodextrin compared with an oil-in-water emulsion of the drug (Diprivan). Propofol had the greatest potency on tracheal preparations with spontaneous tone (EC 50 = 4.0 ± 0.9 μM). Ketamine preferentially relaxed contractions elicited by carbachol (EC 50 = 120.8 ± 5.2 μM) and had a lower potency than propofol when tone was spontaneous or induced by other tracheal spasmogens. Since propofol was a more effective tracheal relaxant in vitro than ketamine, the possibility that propofol, like ketamine, may inhibit bronchoconstriction during anesthesia should be studied further.