[The effect of alpha receptor-blocking agents on inner ear function (author's transl)]

Area of Science:

• Pharmacology
• Neuroscience
• Otolaryngology

Context:

• Nicergoline is clinically used for conditions like tinnitus, cerebral insufficiency, and sensorineural hearing loss.
• Previous studies indicated Nicergoline increases cerebral blood flow.
• The drug's specific mechanism on the inner ear remained unclear.

Purpose:

• To investigate the effect of Nicergoline on the inner ear's DC potential and potassium activity.
• To elucidate the mechanism behind Nicergoline's observed effects, particularly the fall in DC potential.

Summary:

• Nicergoline administration (0.2 mg/kg) led to a rapid fall in DC potential and hypocapnea.
• An increase in expiratory PCO2 (10-20 mm Hg) was noted.
• Artificial respiration with oxygen prevented the DC potential fall, suggesting a link to hypoxia.

Impact:

• The study demonstrates Nicergoline primarily acts on the respiratory center, increasing blood PCO2.
• This PCO2 increase causes cerebral vasodilation.
• The observed fall in inner ear DC potential is attributed to hypoxia, not a direct drug effect on the inner ear.