Die Wirkung einer alpha-adrenergen Rezeptorblockade auf die Funktionen des Innenohres

Nicergolin is used in the treatment of tinnitus, cerebral insufficiency, and sensorineural hearing loss. An increase of cerebral blood flow was observed after i.v. injection of Nicergolin (0.1 mg/kg). The effect of this drug on the inner ear was studied by measuring the DC potential and K⁺ activity in the endolymph. A rapid fall of the DC potential and hypocapnea were observed after the injection of Nicergolin (0.2 mg/kg). An increase of expiratory P_CO2 (10-20 mm Hg) was also observed. Arteficial respiration with pure oxygen prevented the fall of the DC potential. The present investigation demonstrates that this drug primarily acts on the respiratory center with secondary P_CO2 increase in the blood which then causes the dilatation of cerebral vessels. The fall of the DC potential after the injection of Nicergolin appears to be caused by hypoxia and not by direct effect on the inner ear.