Behavioral pharmacology and toxicology of dimethyl sulfoxide in <i>artemia</i> nauplii: vehicle or positive control?

Dimethyl sulfoxide (DMSO) is a routinely used solvent in toxicology studies that are focused on toxicants with low natural solubility in water. However, prior research suggests that DMSO can alter neurological and behavioral outcomes under some circumstances, which could affect its suitability for neurotoxicology research. The current study evaluated the suitability of DMSO vehicles in an aquatic invertebrate model, <i>Artemia</i> nauplii. Subjects were exposed to solutions of 0.01-1% DMSO and assessed for mortality, motility, morphology, and recovery. In Experiment 1, 1-hr exposures significantly decreased swimming speed and increased rotation rates (0.01%, 1%) (slow, spiral swimming). In Experiment 2, 48-hr exposures suppressed swimming speed (0.1%, 1%), and path rotation (1%) (slower, non-spiral swimming), as well as body length (1%). In Experiment 3, following either 1-hr or 48-hr exposures to 1% DMSO, swimming speed and rotation rate persisted through 4-hr post-treatment, and recovered after a 24-hr washout period. Our results indicate that DMSO does affect motility and related behaviors in <i>Artemia</i> after 1- or 48-hr exposures, that these effects are reversible, and that progressive exposure to DMSO can alter the profile of effects. Consideration must be taken when determining what solvent to use when studying toxicants in aquatic species like <i>Artemia</i>.