RT Journal Article
SR Electronic
T1 Kv3 Channels Contribute to the Excitability of Subpopulations of Spinal Cord Neurons in Lamina VII
JF eneuro
JO eNeuro
FD Society for Neuroscience
SP ENEURO.0510-21.2021
DO 10.1523/ENEURO.0510-21.2021
VO 9
IS 1
A1 Pierce N. Mullen
A1 Nadia Pilati
A1 Charles H. Large
A1 Jim Deuchars
A1 Susan A. Deuchars
YR 2022
UL http://www.eneuro.org/content/9/1/ENEURO.0510-21.2021.abstract
AB Autonomic parasympathetic preganglionic neurons (PGNs) drive contraction of the bladder during micturition but remain quiescent during bladder filling. This quiescence is postulated to be because of recurrent inhibition of PGN by fast-firing adjoining interneurons. Here, we defined four distinct neuronal types within Lamina VII, where PGN are situated, by combining whole cell patch clamp recordings with k-means clustering of a range of electrophysiological parameters. Additional morphologic analysis separated these neuronal classes into parasympathetic preganglionic populations (PGN) and a fast-firing interneuronal population. Kv3 channels are voltage-gated potassium channels (Kv) that allow fast and precise firing of neurons. We found that blockade of Kv3 channels by tetraethylammonium (TEA) reduced neuronal firing frequency and isolated high-voltage-activated Kv currents in the fast-firing population but had no effect in PGN populations. Furthermore, Kv3 blockade potentiated the local and descending inhibitory inputs to PGN indicating that Kv3-expressing inhibitory neurons are synaptically connected to PGN. Taken together, our data reveal that Kv3 channels are crucial for fast and regulated neuronal output of a defined population that may be involved in intrinsic spinal bladder circuits that underpin recurrent inhibition of PGN.