Ciliated neurons lining the central canal sense both fluid movement and pH through ASIC3

Abstract

Cerebrospinal fluid-contacting (CSF-c) cells are found in all vertebrates but their function has remained elusive. We recently identified one type of laterally projecting CSF-c cell in lamprey spinal cord with neuronal properties that expresses GABA and somatostatin. We show here that these CSF-c neurons respond to both mechanical stimulation and to lowered pH. These effects are most likely mediated by ASIC3-channels, since APETx2, a specific antagonist of ASIC3, blocks them both. Furthermore, lowering of pH as well as application of somatostatin will reduce the locomotor burst rate. The somatostatin receptor antagonist counteracts the effects of both a decrease in pH and of somatostatin. Lateral bending movement imposed on the spinal cord, as would occur during natural swimming, activates CSF-c neurons. Taken together, we show that CSF-c neurons act both as mechanoreceptors and as chemoreceptors through ASIC3 channels, and their action may protect against pH-changes resulting from excessive neuronal activity.

GABAB receptors modulate Ca2+ but not G protein‐gated inwardly rectifying K+ channels in cerebrospinal‐fluid contacting neurones of mouse brainstem

“…; Jalalvand et al . ). Thus, in CSF‐cNs, variation in intracellular Ca 2+ would affect PKD2L1 activity and in turn CSF‐cN excitability.…”

“…Note that spinal CSF‐cNs in lower vertebrates such as lampreys have been shown to exhibit glutamatergic transmission engaging both AMPA and NMDA receptors (Jalalvand et al . ). Whether this difference is the consequence of NMDA receptor loss of expression in mammalian CSF‐cNs during evolution or more simply a different glutamatergic signalling between CSF‐cNs localised in brainstem and spinal cord remains an open question.…”

“…; Jalalvand et al . ). PKD2L1 channels are non‐selective cationic channels that produce enough depolarisation to trigger action potentials and therefore they contribute to setting the excitability of CSF‐cNs (Orts‐Del'Immagine et al .…”

Cloning of the GABAB Receptor Subunits B1 and B2 and their Expression in the Central Nervous System of the Adult Sea Lamprey

“…The present results show expression of the GABA B transcripts in the dendrites of CSF-c cells of the spinal cord. Currently, some functions have been proposed for CSF-c neurons in controlling the composition of the CSF and releasing substances into the ventricular system (Vígh et al, 2004; Jalalvand et al, 2016). The GABA B receptor in these cells could play a role for detecting GABA in the CSF.…”

A Cytosolic Amphiphilic α-Helix Controls the Activity of the Bile Acid-sensitive Ion Channel (BASIC)

“…ASICs are mainly neuronal channels, which are activated by a sudden increase in the extracellular proton concentration (4). They are involved in the sensation of pain and mechanical stimuli, synaptic transmission, and various cognitive processes (5)(6)(7)(8)(9)(10)(11)(12). ENaC is mainly involved in the absorption of Na ϩ in a variety of tissues.…”