distal dendrite

Definition

Target type: cellularcomponent

The dendrite of the dendritic tree that is farthest away from the neuronal cell body (the soma). [GOC:aruk, GOC:bc, PMID:20629984]

Distal dendrites are the farthest branches of a neuron's dendrite, extending away from the cell body and the proximal dendrites. They play a crucial role in receiving synaptic inputs from other neurons, particularly those involved in long-range communication. Distal dendrites are characterized by their specialized structure and molecular composition, which allows them to integrate and process incoming signals.

**Structure:**
* **Thin and branched:** Distal dendrites are typically thinner and more extensively branched than proximal dendrites, maximizing their surface area for receiving synaptic inputs.
* **Spines:** Many distal dendrites possess small, mushroom-shaped protrusions called spines, which serve as the primary sites of excitatory synaptic contacts. Spines provide a compartmentalized environment for signal processing and plasticity.
* **Cytoskeletal elements:** The cytoskeleton of distal dendrites is composed of microtubules, microfilaments, and intermediate filaments. These elements provide structural support, regulate dendritic morphology, and facilitate the transport of molecules along the dendrite.

**Molecular composition:**
* **Receptors:** Distal dendrites express a variety of receptors for neurotransmitters, including glutamate receptors (AMPA, NMDA, and kainate), GABA receptors, and acetylcholine receptors. These receptors mediate the postsynaptic responses to incoming signals.
* **Signaling molecules:** Distal dendrites contain a diverse array of signaling molecules, such as kinases, phosphatases, and second messengers. These molecules contribute to signal transduction and plasticity within the dendrite.
* **Transporters:** Distal dendrites possess transporter proteins that regulate the uptake and release of neurotransmitters, ensuring proper synaptic function.

**Function:**
* **Signal reception:** Distal dendrites receive synaptic inputs from other neurons, integrating information from various sources.
* **Signal processing:** Distal dendrites are the sites of signal processing, where incoming synaptic signals are integrated and modulated.
* **Plasticity:** Distal dendrites exhibit significant plasticity, allowing their structure and function to be modified in response to experience. This plasticity underlies learning and memory formation.

**Examples:**
* **CA1 pyramidal neurons:** Distal dendrites of CA1 pyramidal neurons in the hippocampus receive inputs from the entorhinal cortex and participate in spatial memory formation.
* **Purkinje cells:** Distal dendrites of Purkinje cells in the cerebellum receive inputs from parallel fibers and play a role in motor coordination and learning.

Overall, distal dendrites are highly specialized cellular compartments that play a critical role in neuronal communication and synaptic plasticity. Their unique structure and molecular composition allow them to integrate incoming signals, process information, and contribute to the complex functions of the nervous system.'
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Proteins (1)

Compounds (13)