Kv1 channels selectively prevent dendritic hyperexcitability in rat Purkinje cells.
Purkinje cells, the sole output of the cerebellar cortex, encode the timing signals required for motor coordination in their firing rate and activity pattern. Dendrites of Purkinje cells express a high density of P/Q-type voltage-gated calcium channels and fire dendritic calcium spikes. Here we show that dendritic subthreshold Kv1.2 subunit-containing Kv1 potassium channels prevent generation of random spontaneous calcium spikes. With Kv1 channels blocked, dendritic calcium spikes drive bursts of somatic sodium spikes and prevent the cell from faithfully encoding motor timing signals. The selective dendritic function of Kv1 channels in Purkinje cells allows them to effectively suppress dendritic hyperexcitability without hindering the generation of somatic action potentials. Further, we show that Kv1 channels also contribute to dendritic integration of parallel fibre synaptic input. Kv1 channels are often targeted to soma and axon and the data presented support a major dendritic function for these channels.
Khavandgar
Simin
S
Department of Neuroscience, Albert Einstein College of Medicine, 506 Kennedy Center, 1410 Pelham Parkway South, Bronx, NY 10461, USA.
Walter
Joy T
JT
Sageser
Kristin
K
Khodakhah
Kamran
K
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D020865:Calcium Channels, P-Type / Q000502:physiology; D020907:Calcium Channels, Q-Type / Q000502:physiology; D003712:Dendrites / Q000502:physiology*; D004546:Elapid Venoms / Q000494:pharmacology; D066298:In Vitro Techniques; D015640:Ion Channel Gating / Q000502:physiology; D011689:Purkinje Cells / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D051637:Shaker Superfamily of Potassium Channels / Q000502:physiology*; D012964:Sodium / Q000378:metabolism; D013569:Synapses / Q000502:physiology
D020865:Calcium Channels, P-Type; D020907:Calcium Channels, Q-Type; D004546:Elapid Venoms; D051637:Shaker Superfamily of Potassium Channels; C020273:dendrotoxin; D012964:Sodium; D002118:Calcium