Recordings in an integrating central neuron reveal the mode of action of isoeugenol

Although isoeugenol is one of the most widely used anesthetics in fish, its actual mode of action and thus its applicability for particular interventions is poorly understood. Here we determined effects of isoeugenol on various aspects of sensory and neural function, taking advantage of intracellular in vivo recordings in a uniquely suited identified neuron, the Mauthner neuron in the brain of goldfish. We show that isoeugenol strongly affects hearing and vision, but sensitivity and time course of action differed largely in these two senses. The action potential, chemical and electric synaptic transmission at the central neuron were not affected at low but efficient anesthesia. Effects seen at high concentration thereby do not support current views of how isoeugenol might act on central neurons. We show that isoeugenol is highly useful to anesthetize fish for handling, but that in more severe treatment its application needs to be carefully adapted to task. In vivo intracellular recordings from the goldfish Mauthner neuron reveal the mode of action of isoeugenol, which is a widely used anaesthetic in fish.

Automated summary

This study used intracellular in vivo recordings in the Mauthner neuron of goldfish to determine the effects of isoeugenol on sensory and neural function. The research found that isoeugenol strongly affects hearing and vision, with significant differences in sensitivity and time course of action. The study also showed that isoeugenol is highly useful for fish anesthesia during handling, but its application needs to be carefully adapted for more severe treatment.