Repetitive optogenetic stimulation of glutamatergic neurons: An alternative to NMDA treatment for generating locomotor activity in spinalized zebrafish larvae

Neuronal circuits within the spinal cord have the capacity to produce rhythmic locomotor activity in isolation from the brain. Application of exogenousN‐methyl‐d‐aspartate (NMDA) is commonly used to experimentally excite these networks to produce locomotor activity. Here, we demonstrate that repetitive optogenetic activation of spinal vesicular glutamate transporter 2a‐expressing neurons is a viable, and potentially more biologically‐relevant, alterna tive to NMDA bath application for studying locomotor network modulation. AbstractN‐methyl‐d‐aspartate (NMDA) application has conventionally been used to activate spinal networks to induce locomotion in spinalized animals. We recently described an alternative approach in which application of continuous blue light activates channelrhodopsin‐2 invesicular glutamate transporter 2a (vglut2a) ‐expressing spinal neurons to produce organized, rhythmic locomotor activity in spinally‐transected larval zebrafish. This technique arguably enhances research validity, because endogenous glutamate is released into existing synapses instead of activating only a subset of glutamatergic (NMDA) re ceptors with an exogenous compound. Here, we explored the viability of this approach in the context of using it for longer‐term experiments. Fictive swimming was induced through repetitive application of 10‐s blue light stimuli to spinalized preparations for up to 60 min at intervals of 1, 3, o r 15 min. Locomotor activity was ...
Source: Physiological Reports - Category: Physiology Authors: Tags: ORIGINAL ARTICLE Source Type: research