title: Effects of high-K+, Na+-deficient solution on contractility of the smooth muscles of the bovine trachea.
abstract: A high-K+, Na+-deficient (I-154 K+) solution induced contraction followed by gradual relaxation of the smooth muscles of the bovine trachea, while hyperosmotic addition of 65 mM KCl induced a large sustained contraction. Exposure of the muscle to the I-154 K+ solution induced an increase in the ratio of cellular water content and a sustained increase in oxidized flavoprotein fluorescence or reduced pyridine nucleotide fluorescence. The I-154 K+ solution also induced a sustained increase in [Ca2+]i level. Decreases in developed tension and increases in cellular water content were both prevented by the addition of sucrose or NaCl but not pyruvate. Substitution of KI for KCl in the I-154 K+ solution produced a greater inhibition of contraction, while substitution with K-propionate produced no inhibition of contraction. Moreover, decreases in developed tension and increases in cellular water content were both prevented by addition of 100 microM 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS), but not 10 microM bumetanide or 1 mM acetazolamide. In conclusion, I-154 K+ solution induced-relaxation in the bovine trachea may be due to swelling of smooth muscle cells and the mechanism of swelling is probably involved in DIDS-sensitive anion movement.
authors.affiliation: Division of Veterinary Pharmacology, Nippon Veterinary and Life Science University, Tokyo, Japan.
authors.forename: Takeharu
authors.initials: T
authors.lastname: Kaneda
authors.forename: Reiko
authors.initials: R
authors.lastname: Sakaguchi
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Shimizu
authors.forename: Norimoto
authors.initials: N
authors.lastname: Urakawa
authors.forename: Shinjiro
authors.initials: S
authors.lastname: Nakajyo
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000086:Acetazolamide / Q000494:pharmacology; D000818:Animals; D002034:Bumetanide / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D005260:Female; D005420:Flavoproteins / Q000378:metabolism; D005470:Fluorometry; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D011189:Potassium Chloride / Q000494:pharmacology*; D011742:Pyrimidine Nucleotides / Q000378:metabolism; D012964:Sodium / Q000172:deficiency*; D049994:Sodium Potassium Chloride Symporter Inhibitors / Q000494:pharmacology; D014132:Trachea / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology
chemical_list: D005420:Flavoproteins; D011742:Pyrimidine Nucleotides; D049994:Sodium Potassium Chloride Symporter Inhibitors; D002034:Bumetanide; D011189:Potassium Chloride; D012964:Sodium; D000086:Acetazolamide; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D002118:Calcium