and loop diuretics have rapid, acute ototoxic side effects through an action on the co-transporter in vestibular dark cells. These acute ototoxic side effects inhibit ion transport resulting in accumulation of ions in the extracellular space leading to edema. The apical membranes of the dark cells also have a K+ channel which is formed of two subunits, the KCNE1 regulatory protein and the KCNQ1 channel proteins.[8] This channel provides the pathway through which K+ is secreted into the endolymph. As a result, mutations in the KCNE1 gene disrupt endolymph production in the vestibular system, leading to the collapse of the epithelia of the roof of the utricle, saccule and ampullae, as well as dysfunction of the vestibular sensory organs. Research Many species (with recent studies done on dogs) are affected by balance disorders and hearing problems that can be caused by a problem in the dark-cell areas in the vestibular endorgans. Studies researching damaged dark cells due to genetic abnormalities or therapeutics are very important in attempting to understand the onset and mechanism of said balance impairments. Dogs have been used as models due to similarities between humans and dogs with regards to inner ear size, inner ear lesions and susceptibility to ototoxins. References Epithelial cells