Induction of non-specific airway hyperreactivity by potassium channel blockade in rat isolated trachea.
1. The exposure of rat isolated tracheal segment to the K(+)-channel inhibitor tetraethylammonium (TEA, 10 mM) for a period of 10-15 min generally produced little or no contractile response. 2. Cooling (10 C) provocation alone usually produced small (10 +/- 3% acetylcholine maximum) contractile responses. 3. In the presence of TEA (10 mM, 10-15 min exposure), rat trachea exhibited airway hyperreactivity to acetylcholine, 5-hydroxytryptamine (5-HT) and cooling. It also increased the peak tension induced by 5-HT. 4. TEA-induced airway hyperreactivity to cooling was significantly inhibited in Ca2(+)-free Krebs solution suggesting an important role for extracellular Ca2+ influx. 5. We conclude that the blockade of potassium channels with TEA induces non-specific airway hyperreactivity to cooling, 5-HT and acetylcholine in rat isolated tracheal segments.
Chand
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Wallace Laboratories, Division of Carter-Wallace, Inc., Cranbury, New Jersey 08512.
Diamantis
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W
Sofia
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D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D015221:Potassium Channels / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000494:pharmacology; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology*; D014132:Trachea / Q000187:drug effects* / Q000502:physiology
D015221:Potassium Channels; D013757:Tetraethylammonium Compounds; D012701:Serotonin; D019789:Tetraethylammonium; D000109:Acetylcholine; D002118:Calcium