In vivo assay for the evaluation of the effect of anesthesia on locomotor activity in the weakly electric fish Apteronotus leptorhynchus

Despite a nearly 200-year long history of anesthesiology, there is a persistent need for new anesthetics with improved safety and specificity, both in animals and humans. The identification and characterization of candidate molecules for the development of such novel drugs depends crucially on suitable in vivo assays. Ideally, these assays test for gradual behavioral outcomes and for the possibility of differential effects on different behaviors and/or neural functions induced by an anesthetic agent. To accommodate these features, we have developed an in vivo assay, based on analysis of amplitude modulations of the electric organ discharge of the weakly electric fish Apteronotus leptorhynchus. It provides a quantitative measurement of the gradual changes in locomotor activity induced by anesthetics. An extension of this assay offers the opportunity for simultaneous evaluation of the effects of anesthetics on two neural functions of the brainstem oscillator that controls the fish's electric behavior. As a distinctive, unique feature, this multimodal Neuro-Behavioral Assay collects all data utilized for analysis from a single non-invasive recording of the electric organ discharge of the fish.