Effect of endoplasmic Ca2+-ATPase inhibitors on cochlear potentials in the guinea-pig.
The effect of endoplasmic Ca2+-ATPase inhibitors on cochlear potentials was examined in the guinea-pig. Perilymphatic perfusion with thapsigargin (10[-6] M) produced a significant decrease in the amplitudes of cochlear microphonics, negative summating potential and compound action potential, and a significant prolongation of N1 latency with no change in the endocochlear potential. These changes were all dose dependent. Another endoplasmic Ca2+-ATPase inhibitor, cyclopiazonic acid (10[-5] M), produced the same effects as thapsigargin on cochlear potentials. These results suggest that endoplasmic Ca2+-ATPase inhibitors may have inhibitory functions on cochlear potentials.
Nario
K
K
Department of Otolaryngology, Nara Medical University, Kashihara City, Japan.
Kitano
I
I
Mori
N
N
Matsunaga
T
T
D000818:Animals; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors*; D003051:Cochlea / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006168:Guinea Pigs; D007211:Indoles / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D019284:Thapsigargin / Q000494:pharmacology
D004791:Enzyme Inhibitors; D007211:Indoles; D019284:Thapsigargin; D000252:Calcium-Transporting ATPases; C000543:cyclopiazonic acid