9/25/2023 0 Comments Scn1a dendrite axonNeurons in particular are highly compartmentalized into distinct axonal and dendritic domains of the plasma membrane. Our results reveal a conserved endocytic clearance mechanism in the AIS to maintain neuronal polarity by reinforcing axonal and dendritic compartment membrane boundaries.Ĭellular compartmentalization is a fundamental feature of eukaryotic cells, which enables them to organize biochemical reactions and create functional specializations 4. Therefore, endocytic removal of polarized receptors that diffuse into the AIS serves as a membrane-clearance mechanism that is likely to work in conjunction with the known AIS diffusion-barrier mechanism to maintain neuronal polarity on the plasma membrane. Forcing receptor interaction with the AIS master organizer, ankyrinG, antagonizes receptor endocytosis in the AIS, causes receptor accumulation in the AIS, and leads to polarity deficits with subsequent morphological and behavioural defects. Here we find that in Caenorhabditis elegans, mouse, rat and human neurons, dendritically and axonally polarized transmembrane proteins are recognized by endocytic machinery in the AIS, robustly endocytosed and targeted to late endosomes for degradation. How the AIS maintains polarity between these compartments is not fully understood. The axon initial segment (AIS) is a specialized domain that separates a neuron’s morphologically, biochemically and functionally distinct axon and dendrite compartments 2, 3. Reference: Synapses, Neurons and Brains course in Coursera by Idan Segev.Neurons are highly polarized cells that face the fundamental challenge of compartmentalizing a vast and diverse repertoire of proteins in order to function properly 1. If the sum of the potentials reaches a threshold, a spike is generated that moves along the axon. All the potentials move towards the soma where all of them are summed up. Thus the dendritic tree gets the post-synaptic potentials from the axons. So, the synapse can be viewed as a digital-to-analogue converter.Įxcitatory (Red) and Inhibitatory (Cyan) axons make connection with the dendritic tree (Blue) via synapse (green). The potential in the spine is an analogue one. The potential in the axon cell is all or none, which is called action potential. The transfer of these neurotransmitters create voltage difference in the axon and the spine. The axon contains small vesicles (neurotransmitter molecules). Red: Dendritic trees, Blue: Axonal trees.įigure 6: Morphometric-based neuron classificationįigure 7: Spiking pattern based neuron classificationįigure 8: Synapse - connecting chemical between pre-synaptic axon and post-synaptic dendritic spine.įigure 9: Synapse - a digital-to-analogue signal converter.Īxon and dendritic spines are separated by synapse. Usually, principal neurons are excitatory and the interneurons are inhibitatory.įigure 5: Principal neurons and interneurons. Principal neurons project to other brain regions, while interneurons project to local regions. Neuron can be classified based on different categories. Typically, there are 10,000 synapse connection in a dendritic tree. Dendritic spines are the regions where synapses are made on to. There are various types of dendrites -Purkinje Cell, Starburst amacrine cell, CA1 Pyramidal cell, etc.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |