Positive and negative DC potential in the vestibular system of pigeons

DC potential in the ampulla of pigeons was studied using a glass microelectrode. After the extirpation of the cochlear duct no change in the DC potential was found. A reduction of the negative DC potential due to anoxia (anoxia-sensitive negative potential, ASNP) was found in the ethacrynic acid (EA)-intoxicated ear, while this finding was minimal or absent in the ouabain-intoxicated ear. The perilymphatic perfusion with K(+)-substituted Ringer's solution resulted in a rapid reduction of the negativity due to EA or ouabain. These findings indicate that the positive DC potential in the ampulla seems to be produced by itself and K+ diffusion potential is the main source of negative DC potential. ASNP may be the unique potential in the EA-intoxicated ear in warm-blooded animals.