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York University uses Axon Patch-Clamp instruments to investigate the roles of pannexin channels in epilepsy

York University

Georg Zoidl

Paige Whyte-Fagundes

MultiClamp 700B Microelectrode Amplifier

Axon Digidata 1550B Low-Noise Data Acquisition System plus HumSilencer

pCLAMP 11 Software Suite

The Challenge

The Zoidl lab at York University, Canada, investigates the roles of pannexin channels in the nervous system in both physiological and pathological contexts, primarily using zebrafish larvae as the model organism in their research.

The focus is to settle a conflict in the literature about the role of pannexin1 (Panx1) in seizures that has been ongoing for the past decade.

Taking advantage of gene editing panx1 genes to create loss of function mutations, the Zoidl lab has established an epilepsy model in zebrafish to answer the question of whether Panx1 channels have distinct roles in seizures. Using electrophysiological tools, they record local field potentials from seizure activity in selected neuronal networks of 6 – 7-day old zebrafish larvae in vivo.

The team keeps the neurocircuitry intact during recordings and pairs electrophysiology data with results from behavioral phenotyping experiments, allowing them to gain new insights into the role of Panx1 in epilepsy. Like many other electrophysiologists, they are required to deal with the challenge of line-frequency noise interference in their electrophysiology rig.

Axon-2

The Solution

The Axon Digidata 1550A/B HumSilencer feature allows the team to eliminate the 50/60Hz line-frequency noise, revealing the biological signal. The built-in adaptable HumSilencer feature can adapt to changing line-frequency noises over time. The adaptive noise learning can be disabled in special circumstances so that the patterns of noises can be stored during the entire course of recording. The stored noise pattern can be reset before or after the end of each new recording.

"Our rig is equipped to measure field recordings from 6-7 day old zebrafish larvae in vivo. We have had great success in doing so, and there is no question that the sensitivity of the Axon equipment is instrumental in enabling us to pursue investigating the circuitry of our novel genetically modified zebrafish lines."

The Results

The senior PhD student, Paige Whyte-Fagundes, has been integral in establishing the electrophysiological setup to record the zebrafish in vivo and piloting the project investigating Panx1 in epilepsy.

The team members intend to use their current electrophysiological setup to investigate physiological variances in the neural circuitry of pannexin channels across a range of genetically modified zebrafish lines. So far, they have been able to address fundamental questions regarding brain rhythms associated with the visual processing of light stimuli in panx1 knockout fish. They have also established the neuroprotective properties of Panx1 in their seizure model and also have uncovered a way to repurpose an FDA approved drug to reduce seizure activity in zebrafish.

In a recent paper, they report on the relationship between panx1a knockout in zebrafish, altered visuomotor behavior and dopaminergic signaling, in research that combines RNA-seq analysis, Real-Time PCR, visual-motor behavior analysis and in vivo electrophysiology.

Visuomotor deficiency in panx1a knockout zebrafish is linked to dopaminergic signaling

You can find out more about the Georg Zoidl Lab on their ResearchGate profile