The cellular target of streptomycin (STP) was investigated by analyzing the activity of glutamate decarboxylase (GAD) or choline acetyltransferase (ChAT) enzymes of synthesis of GABA and acetylcholine (Ach), respectively, [supposedly located in hair cells (GAD) or efferent terminals (ChAT)] in control and in 50 day-STP-treated colored guinea pig vestibular homogenates. Vestibular and auditory function were assessed by measuring postrotatory nystagmus response (PNR) and auditory brainstem evoked potentials (ABP). Morphological changes were followed by light and electron microscopy. STP-treated animals exhibited a GAD decrease of 83.6% with respect to controls whereas ChAT did not suffer any change. Assessment of PNR and ABP showed that STP affected only the former since animals lost it between the 20th and the 30th day of treatment, whereas ABP was not modified. Morphological experiments detected vestibular hair cell deterioration as the only cell type affected by STP. These results confirm the predilection of STP to affect vestibular function by damage to hair cells and show that this effect can be followed by measurement of GAD and ChAT in the vestibule as markers for hair cells and efferent terminals, respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.