Biomaterial Database

Relaxant effect of amiloride on canine tracheal smooth muscle. 1988

I K Krampetz, and R Bose

Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Canada.

Amiloride, a K+-sparing diuretic, relaxed canine tracheal smooth muscle strips contracted isometrically with high potassium (KCl), carbachol, serotonin and histamine. This indicated that relaxation was not linked to an interaction with an agonist specific receptor. Amiloride-induced relaxation was also not mediated through the production of relaxant prostaglandins, or by the endogenous release of catecholamines. During potassium contractions, amiloride addition produced a slow monophasic, dose-dependent relaxation (IC50 = 12.3 microM). In carbachol contracted strips, 1 and 10 microM amiloride induced a slow monophasic relaxation. With 35 to 250 microM, an initial rapid phase (IC50 = 75.5 microM) was superimposed onto this slow phase (IC50 = 23.5 microM), producing a biphasic relaxation. The rates of relaxation decreased with increased external [Na+] regardless of stimulus, suggesting possible competitive inhibition of a sodium-dependent process. Exposure caused a rapid decline in tension followed by a recovery phase. Tension maintenance during potassium contraction decreased transiently upon the addition of acid to a much lesser extent. Amiloride (100 microM) depressed tension recovery after acid exposure in both cases. Based on the known actions of this drug, inhibition of the Na+-H+ antiporter appears to be consistent with these data. This suggests amiloride may well belong to a new class of smooth muscle relaxants.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009126	Muscle Relaxation	That phase of a muscle twitch during which a muscle returns to a resting position.	Muscle Relaxations,Relaxation, Muscle,Relaxations, Muscle
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D002217	Carbachol	A slowly hydrolyzed CHOLINERGIC AGONIST that acts at both MUSCARINIC RECEPTORS and NICOTINIC RECEPTORS.	Carbamylcholine,Carbacholine,Carbamann,Carbamoylcholine,Carbastat,Carbocholine,Carboptic,Doryl,Isopto Carbachol,Jestryl,Miostat,Carbachol, Isopto
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D005260	Female		Females
D000403	Airway Resistance	Physiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow.	Airway Resistances,Resistance, Airway,Resistances, Airway
D000584	Amiloride	A pyrazine compound inhibiting SODIUM reabsorption through SODIUM CHANNELS in renal EPITHELIAL CELLS. This inhibition creates a negative potential in the luminal membranes of principal cells, located in the distal convoluted tubule and collecting duct. Negative potential reduces secretion of potassium and hydrogen ions. Amiloride is used in conjunction with DIURETICS to spare POTASSIUM loss. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p705)	Amidal,Amiduret Trom,Amiloberag,Amiloride Hydrochloride,Amiloride Hydrochloride, Anhydrous,Kaluril,Midamor,Midoride,Modamide,Anhydrous Amiloride Hydrochloride,Hydrochloride, Amiloride,Hydrochloride, Anhydrous Amiloride,Trom, Amiduret
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia