wiki笔记--Lateral hypothalamus--2022/2/23
Lateral hypothalamus
[edit on Wikidata]
The lateral hypothalamus (LH), also called the lateral hypothalamic area (LHA),[1] contains the primary orexinergic nucleus within the hypothalamus that widely projects throughout the nervous system;[2] this system of neurons mediates an array of cognitive and physical processes, such as promoting feeding behavior and arousal, reducing pain perception, and regulating body temperature, digestive functions, and blood pressure, among many others.
(看这些功能，明显是奔着控制交感系统与副交感系统去的，而且应该是促进副交感系统活动，就算是也促进了交感系统，其目的也是为了满足副交感系统对食物的需求。)
[2][3][4] Clinically significant disorders that involve dysfunctions of the orexinergic projection system include narcolepsy, motility disorders or functional gastrointestinal disorders involving visceral hypersensitivity (e.g., irritable bowel syndrome),[3][5] and eating disorders.[6]
The neurotransmitter glutamate and the endocannabinoids（对应着marijuana） (e.g., anandamide) and the orexin neuropeptides orexin-A and orexin-B are the primary signaling neurochemicals in orexin neurons;[3][4][7] pathway-specific neurochemicals include GABA, melanin-concentrating hormone, nociceptin, glucose, the dynorphin peptides, and the appetite-regulating peptide hormones leptin and ghrelin, among others.[3][8]Notably, cannabinoid receptor 1 (CB1) is colocalized on orexinergic projection neurons in the lateral hypothalamus and many output structures（？？？？这话不可解）,[4][7] where the CB1 and orexin receptor 1 (OX1) receptors form the CB1–OX1 receptor heterodimer.[4][9][10]
Contents
· 1Inputs
· 2Outputs
· 3Function
· 4Clinical significance
· 5References
· 6External links
Inputs[edit]
This section needs expansionwith: this list. You can help by adding to it. (July 2015)
· Medial prefrontal cortex[11]
· Central nucleus of the amygdala[12]
Outputs[edit]
See also: Neurotransmitter systems
This section needs expansionwith: The list of outputs included here is not a comprehensive list. You can help by adding to it. (July 2015)
The orexinergic projections from the lateral hypothalamus innervate the entirety of the remainder of the hypothalamus, with robust projections to the posterior hypothalamus
（Its functions include elevation of blood pressure, pupillary dilation, and shivering or body heat conservation。显然都是交感系统兴奋的结果，应该对应着交感的ganglion活动的结果。Descending efferents from the nucleus synapse on the sympathetic neurons of the spinal cord, which exist in the thoracic and lumbar regions in the lateral horns。）
, tuberomammillary nucleus
(the histamine projection nucleus，睡眠时tuberomammillary nucleus彻底不放电。), the arcuate nucleus（对应着leptin）
, and the paraventricular hypothalamic nucleus.[2][3] In addition to the histaminergic nucleus, the orexin system also projects onto the ventral tegmental area dopamine nucleus , locus ceruleus noradrenergic nucleus, the serotonergic raphe nuclei, and cholinergic pedunculopontine nucleus and laterodorsal tegmental nucleus.
(the orexin system同时兴奋所有五个弥散性调节系统，那么在狗吃东西的时候或者那些能让狗觉得可以吃到东西的时候，狗的大脑各方面在orexin system作用下全面提升，智商大大增加，也正是在此时是训练它记忆口令的最佳时机。而orexin system兴奋的这些地方，恰巧被interpeduncular nucleus全面抑制，从而大脑各方面全面下降，智商降低，没有feeding behavior，或者是推迟feeding behavior的发生，推迟智商的上升。脂肪细胞释放的Leptin的升高要抑制orexin system，而且好像nucleus accumbens投射抑制轴突到lateral hypothalamus。食物的引诱是一个很好的提高智商的好办法，但是吃食物时导致的leptin升高会降低智商。还好还有另一种提升智商的生理活动，如果nucleus accumbens的强烈活动会降低lateral hypothalamus活动的话，那么nucleus accumbens主导的重复动作应该也会降低智商。)
[2][8] The histaminergic, dopaminergic, serotonergic, noradrenergic, and cholinergic nuclei which the lateral hypothalamic orexin neurons project onto constitute the primary components of the ascending reticular activating system.[13]
Other output regions include: the ventromedial hypothalamus（负责satiety）, medial and lateral septal nuclei
（medial septal nuclei是acetylcholine system，看样子某些生理反应是会兴奋medial septal nuclei，进而去兴奋海马区。lateral septal nuclei去兴奋VTA）
, central medial amygdala, zona incerta, periaqueductal gray matter, lateral habenula
（唯独不兴奋medial habenula。而medial habenula很有可能直接兴奋interpeduncular nucleus。）
, diagonal band, substantia innominata (contains the nucleus basalis), stria terminalis, prefrontal cortex, various brain stem substructures, including the rostral ventromedial medulla（这里包含着强力疼痛的开与关）, rostral ventrolateral medulla（这与心血管压力感受器相关）, nucleus ambiguus, solitary nucleus, spinal trigeminal nucleus, pontine micturition center, ventral respiratory group, and pontine respiratory group), area postrema, and dorsal nucleus of vagus nerve.[3][8]
（这么多区域，lateral hypothalamus释放的递质难道都是起到兴奋作用吗？起码这里提示我lateral hypothalamus的活动可以解除那些被interpeduncular nucleus抑制的核团。而只有在进食的过程中或预期进食的时候lateral hypothalamus才会全面兴奋-参考巴甫洛夫训狗记中的狗，而进食后提升的leptin又会抑制lateral hypothalamus，所以那些压力大的人靠吃东西来减压的结果是又被leptin带回到抑郁状态，然后重复进食来减压，最终造成过度肥胖。只能说，lateral hypothalamus全面影响重要核团的特点与interpeduncular nucleus相同，只不过二者的功效正好相反。所以，解抑郁的重要生理标识是对食物的生理反应能否正常发生，或者说心情抑郁低落时，那就去吃些好吃的。总的来说，lateral hypothalamus应该是促进副交感系统的活动，那么nucleus accumbens投射到hypothalamus应该总体上起到抑制副交感系统的效果，这样就能允许交感系统活动。）
Cannabinoid receptor 1 (CB1) is colocalized on orexinergic projection neurons in the lateral hypothalamus and many output structures
（这话啥意思？output structures是orexinergic projection neurons的投射目标，output structures的膜上有CB1？orexinergic projection neurons的膜上也有CB1？这些重要的话都没头没尾的，感觉似乎作者不知道哪些基本信息也是重要，所以作者就省略了这些重要的基础内容。）
,[4][7] where the CB1 and orexin receptor 1 (OX1) receptors physically and functionally join together to form the CB1–OX1 receptor heterodimer.[4][9][10] There is substantial anatomical and functional overlap and systemic cross-talk between the endocannabinoid system and orexin system within the central nervous system.[4]
Function[edit]
Through the diverse outputs of the orexin system
（lateral hypothalamus本身核团面积就不小，其output也很广泛，所以有可能二者之间是存在一定的空间拓扑对应关系。）
, the orexin neurons in the lateral hypothalamus mediate an array of functions. Two of the most commonly noted functions of orexin peptides in the lateral hypothalamus are the promotion of feeding behavior and arousal (i.e., wakefulness).[3][6] More generally, the orexinergic neural projections of the lateral hypothalamus are involved in thermoregulation, regulating gastrointestinal motility and gastrointestinal function by way of the dorsal nucleus of the vagus nerve, reducing pain and nociception through several output structures (e.g., periaqueductal gray matter), modulating the rewarding property of stimuli through the ventral tegmental area projections and other outputs in the reward system, regulating energy homeostasis and neuroendocrine functions (e.g., HPA axis, HPG axis, and HPT axis) through other hypothalamic outputs, and regulating visceral functions (e.g., respiration, blood pressure, and micturition) via a group of structures in the brain stem, among other functions.[3][5][14]
The endocannabinoid system and the orexin system mediate many of the same cognitive and physical effects, and a significant overlap in their function and localization has been noted in a 2013 medical review;[4] the CB1–OX1 receptor heterodimerproduces a 100-fold amplification of the potency of the orexin receptor 1-mediated ERK pathway signaling.[4] Unique functional interactions have been noted as well, such as an OX1-induced CB1 pressor response in the rostral ventrolateral medulla.[6][15][16]
Clinical significance[edit]
Narcolepsy is associated with a marked reduction in the number of orexinergic projection neurons from the lateral hypothalamus and very low orexin peptides in cerebrospinal fluid.[17] This has been identified as the mechanism responsible for narcoleptic symptoms.[17]
Evidence suggest that OX1 neurons that synapse onto the dorsal nucleus of the vagus nerve and parts of the brain stem may play a role in the pathophysiology of chronic pain and visceral hypersensitivity in functional gastrointestinal disorders.[3][5]
