Role of ATP-sensitive K+ channels in anoxia-sensitive negative potential of endolymph.
To investigate the possible role of the ATP-sensitive K+ channels (KATP channels) in the generation of the anoxia-sensitive negative potential (ASNP), the effects of the treatment with glybenclamide and diazoxide on the endocochlear potential (EP) and K+ activity (AK) in the scala media were examined with double-barrelled K(+)-selective microelectrodes. The experiments were carried out in guinea pig cochleae, using glybenclamide as a KATP channel blocker and diazoxide as a KATP channel opener. Perilymphatic perfusion of glybenclamide decreased the amplitude of the ASNP and shortened its duration, whereas perfusion of diazoxide increased ASNP amplitude and prolonged its duration. Glybenclamide enhanced the decrease of endolymphatic AK by anoxia, whereas diazoxide suppressed this AK decrease. The results suggest that KATP channels may be involved in the generation of the ASNP.
Kitano
I
I
Department of Otolaryngology, Nara Medical University, Japan.
Mori
N
N
Matsunaga
T
T
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001479:Basal Ganglia / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015687:Cell Hypoxia / Q000502:physiology; D003051:Cochlea / Q000187:drug effects* / Q000378:metabolism; D003981:Diazoxide / Q000494:pharmacology; D004232:Diuretics / Q000494:pharmacology; D004573:Electrolytes; D004710:Endolymph / Q000187:drug effects* / Q000378:metabolism; D005665:Furosemide / Q000494:pharmacology; D005905:Glyburide / Q000494:pharmacology; D006168:Guinea Pigs; D007004:Hypoglycemic Agents / Q000494:pharmacology; D008839:Microelectrodes; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000187:drug effects*; D012533:Scala Tympani / Q000187:drug effects; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D000959:Antihypertensive Agents; D004232:Diuretics; D004573:Electrolytes; D007004:Hypoglycemic Agents; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D005665:Furosemide; D000255:Adenosine Triphosphate; D000254:Sodium-Potassium-Exchanging ATPase; D003981:Diazoxide; D005905:Glyburide