The effect of changes in ambient oxygen concentration on the bioelectric properties of middle ear mucosa.
The purpose of the present study was to compare the effect of 24 h of exposure to 7% O2 (normal middle ear physiological conditions) vs. 21% O2 (found in the middle ear after ventilation tube placement) on transepithelial Na+ absorption and Cl- secretion in cultured gerbil middle ear epithelial cell monolayers. Although no difference in apical Na+ absorption was identified, the UTP-induced stimulation of apical Cl- secretion in the presence of apical Na+ channel blockade with amiloride was significantly enhanced after exposure to 21% O2 compared with 7% O2 exposure. In the presence of a calcium-activated Cl- channel inhibitor, DIDS, UTP-induced stimulation of Cl- secretion after 21% O2 exposure was decreased, suggesting a role for calcium-activated Cl- channels in middle ear Cl- secretion in response to relative hyperoxia.
Mandell
David L
DL
Department of Pediatric Otolaryngology, Children's Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, PA 15213, USA.
Devor
Daniel C
DC
Madia
Joseph V
JV
Lo
Chia-Yee
CY
Hake
Hilary
H
Hebda
Patricia A
PA
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D004432:Ear, Middle / Q000166:cytology* / Q000187:drug effects; D004553:Electric Conductivity; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005849:Gerbillinae; D009092:Mucous Membrane / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D010100:Oxygen / Q000494:pharmacology*; D012964:Sodium / Q000378:metabolism; D026941:Sodium Channel Blockers / Q000494:pharmacology; D014544:Uridine Triphosphate / Q000494:pharmacology
D018118:Chloride Channels; D002712:Chlorides; D026941:Sodium Channel Blockers; D000584:Amiloride; D012964:Sodium; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D010100:Oxygen; D014544:Uridine Triphosphate