Electrophysiological responses of the cochlea to transient asphyxia are influenced by arachidonate metabolites.
The influence of a transient asphyxia on cochlear potentials, i.e. endolymphatic potential (EP), summating potential (SP) and cochlear microphonics (CM) was investigated in guinea pigs when pretreating the animals with various substances interacting with the arachidonic acid (AA) cascade at the level of thromboxane. The controls showed the well-known decline of the EP, CM and the SP increase. When infusing a thromboxane synthetase inhibitor (dazoxiben) or two different thromboxane receptor blockers (daltroban or sulotraban) before the 3-minutes' period of asphyxia was started, the electrophysiological responses of the inner ear (cochlea) could significantly be influenced. The results indicate that a shift of the thromboxane (TXA2)/prostacyclin (PGI2)-balance in favour of the last improve the metabolic conditions for a survival of the cochlea when it is challenged.
Ernst
A
A
Department of Otolaryngology, University of Tubingen, Germany.
Syka
J
J
Mest
H J
HJ
D000704:Analysis of Variance; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism / Q000502:physiology*; D015834:Cochlear Diseases / Q000503:physiopathology*; D011464:Epoprostenol / Q000502:physiology*; D005260:Female; D006168:Guinea Pigs; D007093:Imidazoles / Q000494:pharmacology; D008297:Male; D010648:Phenylacetates / Q000494:pharmacology; D011982:Receptors, Prostaglandin / Q000187:drug effects; D017482:Receptors, Thromboxane; D013449:Sulfonamides / Q000494:pharmacology; D013928:Thromboxane A2 / Q000502:physiology*; D013930:Thromboxane-A Synthase / Q000037:antagonists & inhibitors; D013997:Time Factors
D007093:Imidazoles; D010648:Phenylacetates; D011982:Receptors, Prostaglandin; D017482:Receptors, Thromboxane; D013449:Sulfonamides; C029166:dazoxiben; D016718:Arachidonic Acid; D013928:Thromboxane A2; C040624:sulotroban; D011464:Epoprostenol; D013930:Thromboxane-A Synthase; C051762:daltroban