title: Cellular target of streptomycin in the internal ear.
abstract: 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.
authors: Departamento de Neurociencias, UNAM, D.F., Mexico.
authors: G
authors: G
authors: Meza
authors: I
authors: I
authors: López
authors: M A
authors: MA
authors: Paredes
authors: Y
authors: Y
authors: Peñaloza
authors: A
authors: A
authors: Poblano
mesh_terms: D000818:Animals; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D005260:Female; D005969:Glutamate Dehydrogenase / Q000378:metabolism; D006168:Guinea Pigs; D006198:Hair Cells, Auditory / Q000187:drug effects*; D008297:Male; D013307:Streptomycin / Q000633:toxicity*; D014722:Vestibule, Labyrinth / Q000187:drug effects* / Q000201:enzymology
chemical_list: D005969:Glutamate Dehydrogenase; D002795:Choline O-Acetyltransferase; D013307:Streptomycin