title: Bradykinin increases Na(+)-K(+) pump activity in cultured guinea-pig tracheal smooth muscle cells.
abstract: 1. The effect of bradykinin on the Na+-K+ pump of airway smooth muscle was investigated by measuring ouabain-sensitive (86)Rb(+) uptake in cultured guinea-pig tracheal smooth muscle cells. 2. Bradykinin induced a concentration-dependent increase in ouabain-sensitive (86)Rb(+) uptake, with an EC(50) of 3 nM (pD(2) = 8.50+/-0.10). Stimulation was not affected by indomethacin (1 microM) suggesting that it is not mediated by cycloxygenase products of arachidonic acid. 3. The B(1) receptor agonists Lys-des-Arg(9)-bradykinin and des-Arg(9)-bradykinin had no effect on ouabain-sensitive (86)Rb(+) uptake. In contrast, the B(1) and B(2) receptor agonist Lys-bradykinin induced a concentration-dependent increase in ouabain-sensitive (86)Rb(+) uptake with an EC(50) of 6 nM (pD(2) = 8.21 +/- 0.20). 4. The B(1) receptor antagonist des-Arg(10)-HOE 140 (1 microM) had no effect on bradykinin-stimulated ouabain-sensitive (86)Rb(+) uptake. The B(2) receptor antagonists HOE 140 and WIN 64338 antagonized bradykinin-stimulated ouabain-sensitive (86)Rb(+) uptake with pK(B) values (-log M) of 8.20 +/- 0.08 and 8.11 +/- 0.20 respectively. 5. Reducing extracellular Na+ from 146 mM to 11 mM caused a 53.5% decrease in basal ouabain-sensitive (86)Rb+ uptake and abolished bradykinin-induced uptake. Two inhibitors of the Na(+)-H(+) exchanger, methylisobutyl-amiloride (MIA; 1 - 100 microM) and ethylisopropyl-amiloride (EIPA; 0.1 - 10 microM), inhibited bradykinin-stimulated ouabain-sensitive (86)Rb(+) uptake without affecting basal uptake. 6. These results suggest that bradykinin increases Na+-K+ pump activity of guinea-pig tracheal smooth muscle via stimulation of B(2) receptors and activation of the Na+-H+ exchanger.
authors.affiliation: John B. Pierce Laboratory, 290 Congress Avenue, New Haven, Connecticut, CT 06519, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Dodson
authors.forename: K J
authors.initials: KJ
authors.lastname: Rhoden
mesh_terms: D000818:Animals; D001920:Bradykinin / Q000819:agonists / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D065168:Bradykinin Receptor Antagonists; D002478:Cells, Cultured; D006168:Guinea Pigs; D008297:Male; D008985:Monensin / Q000494:pharmacology; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010042:Ouabain / Q000494:pharmacology; D043782:Receptor, Bradykinin B2; D018002:Receptors, Bradykinin / Q000819:agonists / Q000378:metabolism; D012413:Rubidium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D017923:Sodium-Hydrogen Exchangers / Q000037:antagonists & inhibitors / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D014132:Trachea
chemical_list: D065168:Bradykinin Receptor Antagonists; D043782:Receptor, Bradykinin B2; D018002:Receptors, Bradykinin; D017923:Sodium-Hydrogen Exchangers; D010042:Ouabain; D008985:Monensin; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium; D001920:Bradykinin