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bioRxiv · 10.1101/2020.09.18.303347

Graded calcium spikes differentially signal neurotransmitter input in cerebrospinal fluid contacting neurons of mouse spinal cord

Johnson, E.·Clark, M.·MacLean, C.·Deuchars, J.·Deuchars, S. A.·Johnston, J.
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Abstract

The action potential and its all-or-none nature is fundamental to neural communication. Canonically the action potential is initiated once voltage-gated Na+ channels are activated, and their rapid kinetics of activation and inactivation give rise to the action potentials all-or-none nature. Here we show that cerebrospinal fluid contacting neurons (CSFcNs) surrounding the central canal of the mouse spinal cord employ a different strategy. Rather than using voltage-gated Na+ channels to generate binary spikes, CSFcNs use two different types of voltage-gated Ca2+ channel, enabling spikes of different amplitude. T-type Ca2+ channels generate small amplitude spikes, whereas large amplitude spikes require high voltage-activated Cd2+ sensitive Ca2+ channels. We show that these different amplitude spikes signal input from different transmitter systems; purinergic inputs evoke smaller T-type dependent spikes while cholinergic inputs evoke large T-type independent spikes. Different synaptic inputs to CSFcNs can therefore be signalled by the spike amplitude.

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Johnson, E., Clark, M., MacLean, C., Deuchars, J., Deuchars, S. A., Johnston, J.. 2020-09-19. Graded calcium spikes differentially signal neurotransmitter input in cerebrospinal fluid contacting neurons of mouse spinal cord. https://doi.org/10.1101/2020.09.18.303347

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