Grant: Research Tools and Instruments

A multi-electrode array (MEA) recording system is a ground-breaking*device that enables researchers to monitor the electrical activity from*hundreds of cells at once, from single celled organisms to cells from tissues,*such as neurons or cardiomyocytes. An*MEA device is necessary to measure electrical activity in single cell*eukaryotes, which is not accessible in recordings with conventional*micro-electrodes. *The Spafford lab has*cloned and expressed the first voltagegated sodium and calcium channels from*single cell eukaryotes, and successfully measured their electrical activity in living*choanoflagellates using MEA demonstration units provided by the Axion*Biosystems Maestro Edge and Automate Scientific MED64 Presto in summer 2018. NSERC funded research provides the first*evidence that the electrical activity in animals' nervous systems, was rooted*on an early template provided from the inter-cellular sodium ion signalling between*single cell eukaryotes, in likely ancestors originating more than one billion*years ago. David Spafford has published*on the origins of electrical excitability since the 1990s (Spafford et al. 1996 J. Exp. Biol. 199: 941-948, 1996), and is one of a few who are at*the fore-front of this field (eg. Fux et*al. Frontiers in Physiology, 2018). *The*cardiac action potential is generated with a uniquely invertebrate,*sodium-conducting Cav3 T-type channels in the invertebrate heart, in lieu of Nav1 sodium*channels present in the vertebrate heart (Senatore et al., J. Biol. Chem., 289(17):11952-69,*2014; Guan et al. J. Gen Physiol., in*review 2018). How these differing ion*channels contribute to the electrical activity in the intact heart such as heart*beat timing and the propagation of depolarizing and repolarizing waves along*the sheet of connected heart cells is only available using an MEA device. *An MEA device is also required for analysing the*role of calcium-sensing in Cav3-Type channels with calcium-sensor calmodulin which*was discovered to regulate heart pace-making (Chemin, J., et al., J. Biol. Chem. 292(49):20010-20031,*2017). *Dr. Yim specializes in analyses*of the nano-scale changes in developing neuronal networks, and has ongoing*research in measuring the nerve activity in human IPSC-derived neuronal cultures,*using an MEA device. *Twelve plus*co-applicants from eight different departments have ongoing research involving an MEA device, for a shared multi-user space at the University of*Waterloo.