Meeting Abstract

57.4  Tuesday, Jan. 5  A hammer, not a scalpel: gentamicin ablates all hair cells in the lateral line system. VAN TRUMP, WJ*; COOMBS, S; DUNCAN, K; MCHENRY, MJ; Univ. of California, Irvine; Bowling Green State University; Bowling Green State University; Univ. of California, Irvine wvantrum@uci.edu

Aminoglycoside antibiotics have been used to ablate lateral line hair cells to test the role of this sensory system in the behavior of fish. Studies assessing hair cell damage with SEM have suggested that one of these antibiotics, gentamicin, is toxic to hair cells in one class of lateral line receptor (canal neuromasts), but not the other (superficial neuromasts). This selective toxicity provided the basis for the use of gentamicin as a tool to evaluate the individual roles of the two receptor classes in behavior. The present study investigated the effects of gentamicin on lateral line hair cells in vivo for the first time. This was done using florescent vital dyes (DASPEI and FM1-43), which label functioning hair cells. Contrary to the findings of SEM studies, we found that gentamicin disrupts hair cell function in both receptor classes. Furthermore, by labeling hair cells prior to gentamicin exposure we can conclude that this damage must at least partially be attributed to cell death. These findings were simultaneously discovered in two independent labs working with zebrafish (Danio rerio) and Mexican blind cave fish (Astyanax fasciatus). Our results suggest that gentamicin cannot selectively block classes of lateral line receptors. In light of this result, we have re-evaluated the results of numerous behavioral studies to develop a new view of the role of the lateral line system in fish behavior.