Antagonizing potencies of saturated and unsaturated long-chain free fatty acids to isoflurane in goldfish

Purpose  We have previously reported that myristate, a saturated free fatty acid (FFA) with 14 carbons (C14), antagonizes volatile anesthetics in goldfish. The hydrophobicity and molecular configuration of FFAs may play an important role in the antagonizing effect. To examine their contribution, we investigated the antagonizing potencies of saturated and unsaturated long-chain FFAs in goldfish.Methods  Saturated and monounsaturated FFAs of C14–18 were tested. We determined the anesthetic concentration producing a 50% effect (EC50) of isoflurane in the absence or presence of FFA by observing the escape reaction of goldfish against an electrical stimulus.