page_title: Dendritic spike
section_title: Voltage-Gated Potassium Channel
hierarchical_section_title: Dendritic spike / Voltage-Gated Channels / Voltage-Gated Potassium Channel
caption_attribution_description: Potassium channel KcsA. Calculated hydrocarbon boundaries of the lipid bilayer are indicated by red and blue dots. Protein image from OPM database
context_page_description: In neurophysiology, a dendritic spike refers to an action potential generated in the dendrite of a neuron. Dendrites are branched extensions of a neuron. They receive electrical signals emitted from projecting neurons and transfer these signals to the cell body, or soma. Dendritic signaling has traditionally been viewed as a passive mode of electrical signaling. Unlike its axon counterpart which can generate signals through action potentials, dendrites were believed to only have the ability to propagate electrical signals by physical means: changes in conductance, length, cross sectional area, etc. However, the existence of dendritic spikes was proposed and demonstrated by W. Alden Spencer, Eric Kandel, Rodolfo Llinás and coworkers in the 1960s and a large body of evidence now makes it clear that dendrites are active neuronal structures. Dendrites contain voltage-gated ion channels giving them the ability to generate action potentials. Dendritic spikes have been recorded in numerous types of neurons in the brain and are thought to have great implications in neuronal communication, memory, and learning. They are one of the major factors in long-term potentiation.
context_section_description: Voltage-gated potassium channels are another set of voltage-gated channels that play a significant role in the initiation of dendritic spikes. Voltage-gated potassium channels, similar to voltage-gated sodium and calcium channels, facilitate the movement of cations across the plasma membrane. But unlike voltage-gated sodium and calcium channels, the voltage-gated potassium channel moves cations out of the cell thereby having an inhibitory effect on dendritic spike initiation.
  The transient A-type voltage-gated potassium channel is a specific channel that plays a key role in dendritic spike initiation. The density of voltage-gated sodium and calcium channels is similar in both dendrites and axons; however, the dendritic membrane is far less excitable than the axonal membrane. The difference in excitability can be attributed to the presence of these voltage-gated potassium channels. Voltage-gated potassium channels inhibit the ability of dendrites to generate action potentials and decrease the amplitude of dendritic spikes with increasing distance from the soma. The ability of voltage-gated potassium channels to modulate dendritic signaling may have significant effects on synaptic plasticity.
caption: Potassium channel KcsA.
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