Biomaterial Database

Partial inhibition by epithelium of tracheal smooth muscle relaxation induced by the potassium channel activator, BRL 38227. 1993

D Pavlovic, and E Brione, and D De Vernejoul, and M Aubier

Laboratoire de Pathologie Expérimentale, Unité INSERM 226, Faculté Xavier Bichat, Paris, France.

1. A method is described whereby either the serosal (Out) or epithelial (In) sides of rat isolated tracheae were selectively perfused. Perfusion with BRL 38227 (10(-8)-5 x 10(-6) M; In/Out) of preparations with intact epithelium (+ EP) precontracted with carbachol (10(-6) M; Out/In) produced complete relaxation. Perfusion with aminophylline (10(-5)-10(-3) M; In) of + EP preparations precontracted with carbachol (10(-6) M; Out) also produced complete relaxation. 2. In preparations precontracted with carbachol (10(-6) M) epithelium removal (- EP) increased the sensitivity to the relaxant effect of BRL 38227 (In), but not BRL 38227 (Out) [- log EC50, + EP/- EP; carbachol (In), BRL 38227 (Out): 6.76 +/- 0.11 vs 6.67 +/- 0.15; carbachol (Out), BRL 38227 (In): 5.93 +/- 0.06 vs 6.25 +/- 0.07]. Removal of the epithelium increased also the sensitivity to BRL 38227 (In) of preparations precontracted with a lower concentration (5 x 10(-7) M) of carbachol (Out). [- log EC50, + EP/- EP, carbachol (Out), BRL 38227 (In): 6.19 +/- 0.14 vs 6.58 +/- 0.17]. 3. Removal of the epithelium did not affect the sensitivity to BRL 38227 (In) of preparations precontracted with a higher concentration (5 x 10(-6) M) of carbachol (Out). 4. In both + EP and - EP preparations precontracted with carbachol (10(-6) M; Out), BRL 38227 (In) had a more potent relaxant effect than aminophylline (In) (EC50, BRL 38227 vs aminophylline, + EP/- EP: 5.93 +/- 0.06 vs 3.66 +/- 0.11/6.25 +/- 0.07 vs 3.77 +/- 0.11). 5. In preparations precontracted with carbachol (10-6 M; Out), removal of the epithelium did not affect the sensitivity to aminophylline (In) but increased the degree of precontraction (Tmax) following epithelial but not serosal stimulation with carbachol.6. We conclude that BRL 38227, a K+ channel activator, is a potent relaxant of rat tracheal smooth muscle precontracted with carbachol, and that the effect can be partially inhibited by the presence of an intact tracheal epithelium, whereas the relaxant effect of aminophylline is not.

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
D009130	Muscle, Smooth	Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)	Muscle, Involuntary,Smooth Muscle,Involuntary Muscle,Involuntary Muscles,Muscles, Involuntary,Muscles, Smooth,Smooth Muscles
D011758	Pyrroles	Azoles of one NITROGEN and two double bonds that have aromatic chemical properties.	Pyrrole
D001993	Bronchodilator Agents	Agents that cause an increase in the expansion of a bronchus or bronchial tubes.	Bronchial-Dilating Agents,Bronchodilator,Bronchodilator Agent,Broncholytic Agent,Bronchodilator Effect,Bronchodilator Effects,Bronchodilators,Broncholytic Agents,Broncholytic Effect,Broncholytic Effects,Agent, Bronchodilator,Agent, Broncholytic,Agents, Bronchial-Dilating,Agents, Bronchodilator,Agents, Broncholytic,Bronchial Dilating Agents,Effect, Bronchodilator,Effect, Broncholytic,Effects, Bronchodilator,Effects, Broncholytic
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
D004848	Epithelium	The layers of EPITHELIAL CELLS which cover the inner and outer surfaces of the cutaneous, mucus, and serous tissues and glands of the body.	Mesothelium,Epithelial Tissue,Mesothelial Tissue,Epithelial Tissues,Mesothelial Tissues,Tissue, Epithelial,Tissue, Mesothelial,Tissues, Epithelial,Tissues, Mesothelial
D000628	Aminophylline	A drug combination that contains THEOPHYLLINE and ethylenediamine. It is more soluble in water than theophylline but has similar pharmacologic actions. It's most common use is in bronchial asthma, but it has been investigated for several other applications.	Afonilum,Aminodur,Aminophyllin,Aminophylline DF,Cardophyllin,Carine,Clonofilin,Corophyllin,Diaphyllin,Drafilyn,Duraphyllin,Eufilina,Eufilina Venosa,Euphyllin,Euphyllin Retard,Euphylline,Godafilin,Mini-Lix,Mundiphyllin,Mundiphyllin Retard,Novophyllin,Phyllocontin,Phyllotemp,Somophyllin,Tari-Dog,Theophyllamin Jenapharm,Theophyllamine,Theophyllin EDA-ratiopharm,Theophylline Ethylenediamine,Truphylline,Ethylenediamine, Theophylline,Theophyllin EDA ratiopharm,Theophyllin EDAratiopharm
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