title: Aminoglycoside-induced damage in the statocyst of the longfin inshore squid, Doryteuthis pealeii.
abstract: Squid are a significant component of the marine biomass and are a long-established model organism in experimental neurophysiology. The squid statocyst senses linear and angular acceleration and is the best candidate for mediating squid auditory responses, but its physiology and morphology are rarely studied. The statocyst contains mechano-sensitive hair cells that resemble hair cells in the vestibular and auditory systems of other animals. We examined whether squid statocyst hair cells are sensitive to aminoglycosides, a group of antibiotics that are ototoxic in fish, birds, and mammals. To assess aminoglycoside-induced damage, we used immunofluorescent methods to image the major cell types in the statocyst of longfin squid (Doryteuthis pealeii). Statocysts of live, anesthetized squid were injected with either a buffered saline solution or neomycin at concentrations ranging from 0.05 to 3.0 mmol l(-1). The statocyst hair cells of the macula statica princeps were examined 5 h post-treatment. Anti-acetylated tubulin staining showed no morphological differences between the hair cells of saline-injected and non-injected statocysts. The hair cell bundles of the macula statica princeps in aminoglycoside-injected statocysts were either missing or damaged, with the amount of damage being dose-dependent. The proportion of missing hair cells did not increase at the same rate as damaged cells, suggesting that neomycin treatment affects hair cells in a nonlethal manner. These experiments provide a reliable method for imaging squid hair cells. Further, aminoglycosides can be used to induce hair cell damage in a primary sensory area of the statocyst of squid. Such results support further studies on loss of hearing and balance in squid.
authors.affiliation: Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543; Stanford University School of Medicine, Palo Alto, California 94305; scharr@stanford.edu.
authors.forename: Alexandra L
authors.initials: AL
authors.lastname: Scharr
authors.affiliation: Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543;
authors.forename: T Aran
authors.initials: TA
authors.lastname: Mooney
authors.affiliation: Marine Biological Laboratory, Woods Hole, Massachusetts 02543; Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, California 90095;
authors.forename: Felix E
authors.initials: FE
authors.lastname: Schweizer
authors.affiliation: Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543; Harvard Medical School, Boston, Massachusetts 02114; and Curtin University, Perth, Western Australia 6845, Australia.
authors.forename: Darlene R
authors.initials: DR
authors.lastname: Ketten
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity*; D049832:Decapodiformes / Q000187:drug effects*; D007150:Immunohistochemistry; D009355:Neomycin / Q000633:toxicity*; D046569:Neuroepithelial Cells / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D009355:Neomycin