Editing Dendrite (section)

==Dendrite development==
[[File:Complete neuron cell diagram en.svg|thumb|right|277px]]
During the development of dendrites, several factors can influence differentiation. These include modulation of sensory input, environmental pollutants, body temperature, and drug use.<ref>{{cite journal | vauthors = McEwen BS | title = Stress, sex, and neural adaptation to a changing environment: mechanisms of neuronal remodeling | journal = Annals of the New York Academy of Sciences | volume = 1204 | issue = Suppl | pages = E38–E59 | date = September 2010 | pmid = 20840167 | pmc = 2946089 | doi = 10.1111/j.1749-6632.2010.05568.x | bibcode = 2010NYASA1204...38M }}</ref> For example, rats raised in dark environments were found to have a reduced number of spines in pyramidal cells located in the primary visual cortex and a marked change in distribution of dendrite branching in layer 4 stellate cells.<ref>{{cite journal | vauthors = Borges S, Berry M | title = The effects of dark rearing on the development of the visual cortex of the rat | journal = The Journal of Comparative Neurology | volume = 180 | issue = 2 | pages = 277–300 | date = July 1978 | pmid = 659662 | doi = 10.1002/cne.901800207 | s2cid = 42749947 }}</ref> Experiments done in vitro and in vivo have shown that the presence of afferents and input activity per se can modulate the patterns in which dendrites differentiate.<ref name=Tavosanis />

Little is known about the process by which dendrites orient themselves in vivo and are compelled to create the intricate branching pattern unique to each specific neuronal class. One theory on the mechanism of dendritic arbor development is the Synaptotropic Hypothesis. The synaptotropic hypothesis proposes that input from a presynaptic to a postsynaptic cell (and maturation of excitatory synaptic inputs) eventually can change the course of synapse formation at dendritic and axonal arbors.<ref>{{cite journal | vauthors = Cline H, Haas K | title = The regulation of dendritic arbor development and plasticity by glutamatergic synaptic input: a review of the synaptotrophic hypothesis | journal = The Journal of Physiology | volume = 586 | issue = 6 | pages = 1509–1517 | date = March 2008 | pmid = 18202093 | pmc = 2375708 | doi = 10.1113/jphysiol.2007.150029 }}</ref>

This synapse formation is required for the development of neuronal structure in the functioning brain. A balance between metabolic costs of dendritic elaboration and the need to cover the receptive field presumably determine the size and shape of dendrites. A complex array of extracellular and intracellular cues modulates dendrite development including transcription factors, receptor-ligand interactions, various signaling pathways, local translational machinery, cytoskeletal elements, Golgi outposts and endosomes. These contribute to the organization of the dendrites on individual cell bodies and the placement of these dendrites in the neuronal circuitry. For example, it was shown that β-actin zipcode binding protein 1 (ZBP1) contributes to proper dendritic branching.

Other important transcription factors involved in the morphology of dendrites include CUT, Abrupt, Collier, Spineless, ACJ6/drifter, CREST, NEUROD1, CREB, NEUROG2 etc. Secreted proteins and cell surface receptors include neurotrophins and tyrosine kinase receptors, BMP7, Wnt/dishevelled, EPHB 1–3, Semaphorin/plexin-neuropilin, slit-robo, netrin-frazzled, reelin. Rac, CDC42 and RhoA serve as cytoskeletal regulators, and the motor protein includes KIF5, dynein, LIS1. Dendritic arborization has been found to be induced in cerebellum Purkinje cells by [[substance P]]. <ref>{{Cite journal |last1=Baloyannis |first1=Stavros |last2=Costa |first2=Vassiliki |last3=Deretzi |first3=Georgia |last4=Michmizos |first4=Dimitrios |date=1999 |title="Intraventricular Administration of Substance P Increases the Dendritic Arborisation and the Synaptic Surfaces of Purkinje Cells in Rat's Cerebellum" |url=https://www.tandfonline.com/doi/abs/10.3109/00207450008986495 |journal=International Journal of Neuroscience |volume=101 |issue=1–4 |pages=89–107 |doi=10.3109/00207450008986495 |pmid=10765993 |via=Pub Med|url-access=subscription }}</ref> Important secretory and endocytic pathways controlling the dendritic development include DAR3 /SAR1, DAR2/Sec23, DAR6/Rab1 etc. All these molecules interplay with each other in controlling dendritic morphogenesis including the acquisition of type specific dendritic arborization, the regulation of dendrite size and the organization of dendrites emanating from different neurons.<ref name="urbanska" /><ref name="perycz" />