The effect of adenosine on cochlear potentials in the guinea pig.
The effect of adenosine on cochlear potentials was examined in the guinea pig. Perilymphatic perfusion with 10(-4) M adenosine produced a significant decrease in the amplitudes of cochlear microphonics, negative summating potential (-SP) and compound action potential (CAP) and significant prolongation of N1 latency with no change in the endocochlear potential. The decreases in the amplitudes of -SP and CAP caused by adenosine were dose-dependent. Perilymphatic perfusion with an inactive analogue, 8-bromoadenosine, produced no changes in the cochlear potentials. The A1-receptor agonist, 2-chloro-adenosine, produced a similar change in cochlear potentials to adenosine, while no changes were produced by the A2-receptor agonist, 5'-(N-ethylcarboxamido)-adenosine. These results suggest that adenosine may have a modulatory function through an A1 receptor in the cochlea.
Department of Otolaryngology, Nara Medical University, Japan.
K
K
Nario
I
I
Kitano
N
N
Mori
T
T
Matsunaga
D015762:2-Chloroadenosine / Q000494:pharmacology; D000161:Acoustic Stimulation; D000200:Action Potentials / Q000187:drug effects* / Q000502:physiology; D000241:Adenosine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology*; D019830:Adenosine-5'-(N-ethylcarboxamide); D058668:Adrenergic alpha-1 Receptor Antagonists; D058669:Adrenergic alpha-2 Receptor Antagonists; D000818:Animals; D003051:Cochlea / Q000187:drug effects* / Q000502:physiology; D003055:Cochlear Microphonic Potentials / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D011930:Reaction Time / Q000187:drug effects
D058668:Adrenergic alpha-1 Receptor Antagonists; D058669:Adrenergic alpha-2 Receptor Antagonists; D015762:2-Chloroadenosine; C036038:8-bromoadenosine; D019830:Adenosine-5'-(N-ethylcarboxamide); D000241:Adenosine