Gentamicin-induced changes in RNA content in sensory and ganglionic cells in the hearing organ of the lizard Calotes versicolor. A cytochemical and morphological investigation.

The effect of short-term administration of gentamicin on RNA content in isolated sensory and ganglionic cells in the hearing organ of the lizard Calotes versicolor was investigated. The effects of the drug on this biochemical parameter are compared with ultrastructural changes in sensory cells from the same material. In the first test group, daily intraperitoneal injections for 3 to 6 days resulted in a 30-50% decrease of the amount of RNA in sensory and ganglionic cells. No constant ultrastructural changes were recorded in the sensory cells at this point in time. A second test group received 3 or 5 injections of gentamicin and the animals were then left untreated for 21 days. The reduced RNA content persisted in both sensory cells and in ganglionic cells from animals that received 5 injections, whereas the content of RNA in ganglionic cells from lizards that received 3 injections was restored almost to control values at the end of this 21-day period. In the second test group, definite morphological derangements were observed in the sensory cells. The correlation between cytochemical and morphological findings as well as possible modes of action of gentamicin on inner ear ganglionic and sensory cell RNA content are discussed.