This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
Initial mechanism of action of intra-tympanic gentamicin microwick catheter inseed into inner ear in treatment of Menier's disease 
Select and explain. 
A. Damage outer hair cell, B. Binds to hair cell Na*-K+ ATPase channel, C. Acts on melanoreceptors of outer hair cell, D. Bind to Mg" channel
C: Acts on melanoreceptors of outer hair cell
Answer: C: Acts on melanoreceptors of outer hair cell 
Explanation: Ans. c. Acts on melanoreceptors of outer hair cell Intra-tympanic Gentamicin is used in Menier's Disease, it is Predominantly vestibulotoxic, and acts by destroying the dark cells (melanoreceptors) of the secretary epithelium, thus decreasing the endolymph production Intra-tympanic Gentamicin in Menier's Disease Mechanism of Action: Predominantly vestibulotoxic, and acts by destroying the dark cells (melanoreceptors) of the secretary epithelium,thus decreasing the endolymph production Gentamicin destroys the endolymph secreting dark cells before destroying the sensory vestibular epithelium This treatment has high efficacy in controlling the veigo upto 90%. Regarding Gentamicin mechanism: "The main alternative to the mechanism being destruction of dark cells is the hypothesis that there is a paial damage to the vestibular hair cells. Recent studies in animals suggest that the type-I hair cells are the most sensitive, and the type-II hair cells are more resiliant."