Taurine prevents memory consolidation deficits in a novel alcohol-induced blackout model in zebrafish.

Ethanol is one of the most consumed substance worldwide that impairs learning and memory processes, resulting in amnesia or blackout. Due to the genetic conservation, rich behavioral repertoire, and high pharmacological tractability, the zebrafish (Danio rerio) has emerged as a powerful model organism for assessing preventive strategies against the noxious effects of ethanol in vertebrates. Here, we used an inhibitory avoidance apparatus to investigate the potential preventive effects of taurine in a novel ethanol-induced amnesia model in zebrafish. The experimental tank consisted of two compartments of the same size, one dark and another white, which were separated by a guillotine-type door. Three parallel metal bars coupled to an electrical stimulator were connected on each lateral wall of the dark compartment as electrical stimulus source. Differences on the latency to enter the dark compartment were used as retention indexes. A mild electric shock (125 mA, 3 ±â€¯0.2 V) at 10 and 1000 Hz did not promote significant learning, while 100 Hz facilitated memory retention. Posttraining administration of MK-801 blocked this response, reinforcing the predictive validity of the test. Treatments were performed immediately after the training session using the 100 Hz frequency. Animals were exposed to water (control), taurine (42, 150, 400 mg/L), ethanol (0.25%, 1.0% v/v) or taurine plus ethanol to assess the effects on memory consolidation. Test session was performed 24 h following training. Ethanol at 0.25% did not affect memory consolidation, but 1.0% impaired memory without changing locomotion. Although taurine alone did not modulate learning, all concentrations tested exerted prevented ethanol-induced memory impairment. Overall, we describe a novel ethanol-induced blackout model, where a high ethanol concentration acutely impairs memory consolidation in zebrafish. Moreover, since taurine showed a protective role, we reinforce the growing utility of zebrafish models for assessing the deleterious effects of ethanol and potential therapeutic strategies.

Modulatory action of taurine on ethanol-induced aggressive behavior in zebrafish.

Alcohol is a potent agent for eliciting aggression in vertebrates. Taurine (TAU) is an amino sulfonic acid with pleiotropic actions on brain function. It is one of the most abundant molecules present in energy drinks frequently used as mixers for alcoholic beverages. However, the combined effects of TAU and ethanol (EtOH) on behavioral parameters such as aggression are poorly understood. Considering that zebrafish is a suitable vertebrate to assess agonistic behaviors using noninvasive protocols, we investigate whether TAU modulates EtOH-induced aggression in zebrafish using the mirror-induced aggression (MIA) test. Since body color can be altered by pharmacological agents and may be indicative of emotional state, we also evaluated the actions of EtOH and TAU on pigment response. Fish were acutely exposed to TAU (42, 150, and 400mg/L), EtOH (0.25%), or cotreated with both molecules for 1h and then placed in the test apparatus for 6min. EtOH, TAU 42, TAU 400, TAU 42/EtOH and TAU 400/EtOH showed increased aggression, while 150mg/L TAU only increased the latency to attack the mirror. This same concentration also prevented EtOH-induced aggression, suggesting that it antagonizes the effects of acute alcohol exposure. Representative ethograms revealed the existence of different aggressive patterns and our results were confirmed by an index used to estimate aggression in the MIA test. TAU did not alter pigment intensity, while EtOH and all cotreated groups presented a substantial increase in body color. Overall, these data show a biphasic effect of TAU on EtOH-induced aggression of zebrafish, which is not necessarily associated with changes in body color.