title: Interaction of catecholamine and acetazolamide in the action on the endolymphatic sac direct current potential.
abstract: Our recent studies have revealed that catecholamines depress the endolymphatic sac DC potential (ESP) by beta-adrenergic action, and that acetazolamide (ACTZ), a potent carbonic anhydrase inhibitor, decreases the ESP. The interaction of ACTZ and isoproterenol (Iso), a nonselective beta agonist, in their action on the ESP was examined in the guinea pig. Intravenous administration of Iso (6.25 micrograms/kg/min) and ACTZ (10 mg/kg) reduced the ESP amplitude by 38.5 +/- 5.9% (n = 8) and 39.8 +/- 3.7% (n = 8), respectively. Co-administration of both agents reduced the ESP amplitude by 62.3 +/- 3.3% (n = 8). The ESP change induced by co-administration was significantly larger than that by the administration of each agent alone. Co-treatment with Iso and ACTZ at doses producing near-maximum reduction of the ESP depressed almost all parts of oxygen-dependent components of the ESP. The results suggest that Iso and ACTZ decrease the ESP via mechanisms different from each other, and that oxygen-dependent components of the ESP are composed of Iso- and ACTZ-sensitive parts.
authors.affiliation: Department of Otolaryngology, Kagawa Medical School, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Mori
authors.forename: N
authors.initials: N
authors.lastname: Uozumi
mesh_terms: D000086:Acetazolamide / Q000008:administration & dosage / Q000494:pharmacology*; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D004195:Disease Models, Animal; D004357:Drug Synergism; D004712:Endolymphatic Sac / Q000187:drug effects* / Q000502:physiology / Q000503:physiopathology; D006168:Guinea Pigs; D000860:Hypoxia / Q000503:physiopathology*; D007262:Infusions, Intravenous; D007545:Isoproterenol / Q000008:administration & dosage / Q000494:pharmacology*; D007601:Jugular Veins / Q000187:drug effects; D008954:Models, Biological
chemical_list: D007545:Isoproterenol; D000086:Acetazolamide