Isoproterenol augments ATP-evoked Cl- secretion across canine tracheal epithelium.
Using an Ussing chamber, both the posterior epithelial membrane and cultured epithelial cell monolayers from canine trachea were used for measurements of potential difference (PD) and short circuit current (SCC). Conductance (G) was calculated as the ratio SCC/PD. Adenosine (10(-5) to 10(-3) M) failed to produce any significant increases in PD and SCC. ATP (10(-6) to 10(-4) M) produced a significant transient increase in SCC in a dose-dependent fashion, reaching a peak value within 3 min after stimulation. Isoproterenol (ISOP) at 10(-8) M itself did not significantly alter the SCC value. In both the epithelial membrane and cultured epithelial cells treated with amiloride, however, pretreatment with 10(-8) M ISOP significantly augmented the ATP-induced SCC rise, whereas G did not significantly change. These findings indicate that beta-adrenergic stimulation augments Cl- secretion induced by P2-receptor stimulation in airway epithelial cells.
Satoh
M
M
First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
Yamaya
M
M
Shimura
S
S
Masuda
T
T
Yamamoto
M
M
Sasaki
T
T
Sasaki
H
H
Shirato
K
K
D000200:Action Potentials / Q000187:drug effects; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D002712:Chlorides / Q000378:metabolism*; D004285:Dogs; D004848:Epithelium / Q000187:drug effects / Q000502:physiology; D005260:Female; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D014132:Trachea / Q000187:drug effects* / Q000502:physiology
D002712:Chlorides; D000584:Amiloride; D000255:Adenosine Triphosphate; D007545:Isoproterenol