Effects of Na+ transport inhibitors on guinea-pig tracheal responses to spasmogens.
The effects of ouabain, amiloride, K(+)-free solution and low Na+ (25 mM) solution on the responses to CaCl2 (in Ca(2+)-free, K(+)-depolarizing solution), KCl, acetylcholine, histamine and 5-hydroxytryptamine were studied in guinea-pig isolated trachea. Ouabain (10 microM) did not alter the contractile responses to CaCl2, KCl and acetylcholine but depressed those to histamine and 5-hydroxytryptamine produced in normal Ca2+ (2.5 mM) and Ca(2+)-free (EGTA 0.1 mM) media. Amiloride (0.1 mM), K(+)-free solution, and low Na+ solution depressed responses to acetylcholine, histamine and 5-hydroxytryptamine produced in normal Ca2+ and Ca(2+)-free media. Ouabain and amiloride had no effect on responses of skinned strips to Ca2+. The mechanism of the inhibitory effects of these interventions is uncertain but the findings suggest that the availability of Na+ influences the airway smooth muscle responses to spasmogens.
Cortijo
J
J
Departament de Farmacologia, Facultat de Medicina, Universitat de València, Spain.
Gonzalez
M
M
Ortiz
J L
JL
Morcillo
E J
EJ
D000109:Acetylcholine / Q000494:pharmacology; D000328:Adult; D000584:Amiloride / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D010042:Ouabain / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000187:drug effects*; D014132:Trachea / Q000187:drug effects* / Q000502:physiology
D012701:Serotonin; D010042:Ouabain; D011189:Potassium Chloride; D000584:Amiloride; D006632:Histamine; D000254:Sodium-Potassium-Exchanging ATPase; D000109:Acetylcholine; D002118:Calcium