Monoterpenoids (thymol, carvacrol and S-(+)-linalool) with anesthetic activity in silver catfish (Rhamdia quelen): evaluation of acetylcholinesterase and GABAergic activity

This study evaluated the anesthetic potential of thymol and carvacrol, and their influence on acetylcholinesterase (AChE) activity in the muscle and brain of silver catfish (Rhamdia quelen). The AChE activity of S-(+)-linalool was also evaluated. We subsequently assessed the effects of thymol and S-(+)-linalool on the GABAergic system. Fish were exposed to thymol and carvacrol (25, 50, 75, and 100 mg/L) to evaluate time for anesthesia and recovery. Both compounds induced sedation at 25 mg/L and anesthesia with 50–100 mg/L. However, fish exposed to carvacrol presented strong muscle contractio...