Ex Vivo Whole Nerve Electrophysiology Setup, Action Potential Recording, and Data Analyses in a Rodent Model

Abstract

Ex vivo rodent whole nerves provide a model for assessing the effects of interventions on nerve impulse transmission and consequent sensory and/or motor function. Nerve impulse transmission can be measured through sciatic nerve compound action potential (CAP) recordings. However, de novo development and implementation of an ex vivo whole nerve resection protocol and an electrophysiology setup that retains nerve viability, that produces low noise CAP signals, and that allows for data analysis is challenging. Additionally, some of the existing literature lacks detail and accuracy and may be out of date. This article describes detailed protocols for rodent ex vivo sciatic nerve dissection and handling; importance of an optimal physiologic solution; computer‐aided designs for 3D printing of readily adaptable ex vivo rodent whole nerve electrophysiology chambers; construction of low‐cost, effective suction electrodes; setup and use of nerve stimulators and amplifiers; acquisition of low noise, small voltage CAP data and digital conversion; use of software for data analyses of CAP components; and tips for troubleshooting. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Electrophysiology wiring and hardware setup Support Protocol 1: 3D printing an electrophysiology chamber Support Protocol 2: Building suction electrodes Basic Protocol 2: Sciatic nerve dissection and compound action potential recording Basic Protocol 3: Data export and analysis Support Protocol 3: Preparation of HEPES‐buffered physiologic solution

Experimental Protocols and Analytical Procedures for Studying Synaptic Transmission in Rodent Spinal Cord Dorsal Horn

“…This protocol describes how to assemble the stimulating circuit, record the afferent volleys from the dorsal root (i.e., the sum of action potentials generated by the stimulated fibers), and record field potentials from dorsal horn neurons. For detail set-up of electrophysiological wiring and building of suction electrodes, please see the Current Protocols article Sun et al (2020), which describes compound action potential recording from the sciatic nerve in a rodent model. A similar technique is described here to determine the appropriate stimulus intensities necessary to evoke synaptic responses in dorsal horn neurons.…”

Dose-dependent effects of high intensity focused ultrasound on compound action potentials in an ex vivo rodent peripheral nerve model: comparison to local anesthetics

“…The ex vivo electrophysiology methods used here were described in detail previously 21. Briefly, the ex vivo electrophysiology system consisted of a stimulus isolator (Isostim A320R, World Precision Instruments, Sarasota, Florida, USA), an extracellular amplifier/recording device (SYS-DAM80, World Precision Instruments), an electrophysiology chamber with suction electrodes, and software for stimulation, recording and analyzing CAP signals (WinWCP V.5.5.1 and WinEDR V.3.8.9, John Dempster, University of Strathclyde Glasgow).…”

Schwann cells promote sensory neuron excitability during development

“…and rarely propagated multiple action potential spikes (Figures 1B-1D). This result is in stark contrast to the normal ability of DRG neurons to fire repetitive trains of action potentials in culture 30,32,33 and in vivo [34][35][36][37][38] . Thus, in the absence of glial cells, cultured DRG neurons are hypoexcitable.…”

“…The ex vivo electrophysiology setup and methods used in this study have been detailed elsewhere 34,35 Once placed in the chamber suction electrodes, the nerves were allowed to "rest" for 20 minutes before stimulation and recording occurred. The nerves were first stimulated with 0.1 milliamperes (mA) of current to check for the presence of a compound action potential (CAP).…”