title: Does endogenous or exogenous adenosine facilitate the functional recovery of the cochlea after ischemia?
abstract: The present study was undertaken to determine whether adenosine attenuates cochlear dysfunction induced by transient ischemia. Adenosine or erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA), an adenosine deaminase inhibitor, was administered by perilymphatic perfusion to albino guinea pigs that were subjected to cochlear ischemic episodes of 30-minute duration. The threshold shift of the compound action potential (CAP) from the preischemic value was significantly reduced in the animals perfused with EHNA 1 hour after the onset of reperfusion. However, perfusion of adenosine at concentrations of 100 micromol/L to 10 mmol/L did not reduce the postischemic CAP threshold shift by either 1 hour or 4 hours after the onset of reperfusion. These results suggest that the elevation of the adenosine concentration did not exert a protective effect on the cochlear ischemia-reperfusion injury, and that the protective action of EHNA is unrelated to elevating the adenosine concentration.
authors: Department of Otolaryngology, Institute of Clinical Medicine, University of Tsukuba, Japan.
authors: Keiji
authors: K
authors: Tabuchi
authors: Shigeki
authors: S
authors: Tsuji
authors: Yasutoshi
authors: Y
authors: Asaka
authors: Zenya
authors: Z
authors: Ito
authors: Akira
authors: A
authors: Hara
authors: Jun
authors: J
authors: Kusakari
mesh_terms: D000200:Action Potentials; D000225:Adenine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D000241:Adenosine / Q000008:administration & dosage / Q000494:pharmacology* / Q000502:physiology*; D058892:Adenosine Deaminase Inhibitors; D000818:Animals; D003051:Cochlea / Q000098:blood supply* / Q000502:physiology* / Q000503:physiopathology; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology; D006168:Guinea Pigs; D007511:Ischemia / Q000503:physiopathology*; D020127:Recovery of Function; D015427:Reperfusion Injury / Q000517:prevention & control*; D013997:Time Factors; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D058892:Adenosine Deaminase Inhibitors; D004791:Enzyme Inhibitors; D014665:Vasodilator Agents; C010192:9-(2-hydroxy-3-nonyl)adenine; D000225:Adenine; D000241:Adenosine