The role of potassium ion channels in cough and other reflexes of the airways.
In this study we investigated whether openers of potassium channels, K+ATP--pinacidil and BK+Ca--NS1619, modulate cough reflex and airway smooth muscle (ASM) reactivity in in vivo and in vitro conditions in guinea pigs. The cough reflex was induced by 0.3 M citric acid aerosol given for 3 min during which time a total number of coughs was counted. ASM reactivity in vivo was expressed as the values of specific airway resistance calculated by Pennock. Changes in ASM reactivity in vitro were tested by a tissue bath method. We found that both openers of potassium channels inhibit the citric acid-induced cough. ASM reactivity in vivo was significantly abolished by pinacidil and NS1619, which corresponded with the results of in vitro measurements. Pretreatment by selective blockers, K+ATP--glibenclamide and BK+Ca-tetraethylammonium prevented the above mentioned effects. The results indicate an important role of K+ATP and BK+Ca ion channels in defense reflexes of airways.
Sutovska
M
M
Department of Pharmacology, Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Slovakia. sutovska@jfmed.uniba.sk
Nosalova
G
G
Franova
S
S
D000109:Acetylcholine / Q000494:pharmacology; D000336:Aerosols; D000403:Airway Resistance / Q000187:drug effects; D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology; D019343:Citric Acid; D003371:Cough / Q000139:chemically induced / Q000503:physiopathology*; D005905:Glyburide / Q000494:pharmacology; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D054086:KATP Channels / Q000037:antagonists & inhibitors; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D020110:Pinacidil / Q000494:pharmacology; D010991:Plethysmography; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D024681:Potassium Channels, Calcium-Activated / Q000187:drug effects; D012018:Reflex / Q000187:drug effects / Q000502:physiology*; D015656:Respiratory Mechanics / Q000187:drug effects; D012132:Respiratory Muscles / Q000187:drug effects / Q000502:physiology; D012143:Respiratory Physiological Phenomena / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
D000336:Aerosols; D001562:Benzimidazoles; D054086:KATP Channels; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D014665:Vasodilator Agents; C086491:NS 1619; D019343:Citric Acid; D020110:Pinacidil; D006632:Histamine; D000109:Acetylcholine; D005905:Glyburide