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多巴胺受體D2
位於11號人類染色體的基因 来自维基百科,自由的百科全书
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多巴胺受體D2(Dopamine receptor D2,簡稱D2R),為轉譯自 DRD2 基因的一種多巴胺受體蛋白。D2R最早於1975年為Philip Seeman所發現,並將其命名為「抗精神疾患性多巴胺受體」(antipsychotic dopamine receptor)[8]。D2R為所有抗精神病药物的作用標的。
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功能
D2R屬於一種多巴胺受體,並會與Gi結合。Gi為G蛋白偶联受体的一種亞型,會抑制腺苷酸环化酶的活性[9]。
在小鼠中,齒狀回的neuronal calcium sensor-1(NCS-1)會影響D2R在細胞膜的表現量。這項機制會影響突触可塑性及記憶形成[10]。
同型體
长形式(D2Lh)具有"规范"的序列,并作为经典突触后蛋白发挥作用。[13]短形式(D2Sh)在突触前作为调节突触间隙中多巴胺水平的自身受体发挥作用。[13]D2Sh受体激动时抑制多巴胺释放,拮抗时增加多巴胺释放。[13]第三种D2(更长)的形式不同于270V被VVQ取代的规范序列。[14]
基因組
等位基因變異:
- A-241G
- C132T、G423A、T765C、C939T、C957T,以及G1101A[15]
- Cys311Ser
- -141C insertion/deletion[16]The polymorphisms have been investigated with respect to association with schizophrenia.[17]
Some researchers have previously associated the polymorphism Taq 1A (rs1800497) to the DRD2 gene. However, the polymorphism resides in exon 8 of the ANKK1 gene.[18]DRD2 TaqIA polymorphism has been reported to be associated with an increased risk for developing motor fluctuations but not hallucinations in Parkinson's disease.[19][20]
配體
大多数较老的抗精神病药如氯丙嗪或氟哌啶醇是多巴胺D2受体的非选择性拮抗剂,最多仅对"D2样家族"受体具有选择性,因此与D2、D3、D4以及许多其他受体都可以结合,例如血清素和组胺受体,导致一系列副作用使得它们不适合科学研究。类似,用于治疗帕金森病的较旧的多巴胺激动剂例如溴隐亭和卡麦角林,对一种多巴胺受体的选择性较差,尽管这些药物中大多数确实能起到D2激动剂的作用,但它们也会影响其他多巴胺受体,亚型也是。现今有几种选择性D2配体 (生物化学)可以使用,并且随着进一步的研究,这个数字可能会增加。
- 溴隱亭(Bromocriptine):完全受體致活劑
- Cabergoline(Caberl)
- N,N-Propyldihydrexidine:D1/D5受體制活劑dihydrexidine的類似物,對節後神經元的D2R親和性比節前神經元的D2自體受器高。
- Piribedil:同時也是 D3 受體致活劑及腎上腺素α2受體拮抗劑
- Pramipexole:同時也是D3、D4受體致活劑
- Quinelorane:affinity for D2 > D3
- Quinpirole:同時也是D3受體致活劑
- Ropinirole:完全受體致活劑
- Sumanirole:高選擇性完全受體致活劑
- Talipexole:對D2的親和性高於其他的多巴胺受體,但同時也是腎上腺素α2受體制活劑及5-HT3受體拮抗劑。
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- Aplindore
- 阿立哌唑(Aripiprazole,在美國合法)[21]
- Brexpiprazole/OPC-34712
- Cariprazine
- RP5063
- GSK-789,472 – Also D3 antagonist, with good selectivity over other receptors [22]
- 氯胺酮(Ketamine,同時也為NMDA受體拮抗劑)
- LSD – in vitro, LSD was found to be a partial agonist and potentiates dopamine-mediated prolactin secretion in lactotrophs.[23]LSD is also a 5-HT2A agonist.
- 莫达非尼(Modafinil)
- Roxindole (only at the D2 autoreceptors)
- OSU-6162:亦為5-HT2A部分受體致活劑,acts as "dopamine stabilizer"
- Salvinorin A:亦為κ-鴉片類受體致活劑。
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- Atypical antipsychotics
- Desmethoxyfallypride
- Domperidone – D2 and D3 antagonist; does not cross the blood-brain barrier
- Eticlopride
- Fallypride
- Hydroxyzine (Vistaril, Atarax)
- Itopride
- L-741,626 – highly selective D2 antagonist
- C11 Raclopride radiolabled – commonly employed in positron emission tomography studies[24]
- Typical antipsychotics
- SV 293[25]
- Yohimbine
- D2sh selective (presynaptic autoreceptors)
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- 參見參考文獻[31]。
Protein–protein interactions
The D2 receptor forms receptor heterodimers in vivo (in living animals) with other G protein-coupled receptors; these include:[35]
- D1–D2 dopamine receptor heteromer
- D2–adenosine A2A
- D2–ghrelin receptor
- D2sh–TAAR1[note 1]
The D2 receptor has been shown to form hetorodimers in vitro (and possibly in vivo) with DRD3,[38]DRD5,[39]and 5-HT2A.[40]
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註釋
- D2sh–TAAR1 is a presynaptic heterodimer which involves the relocation of TAAR1 from the intracellular space to D2sh at the plasma membrane, increased D2sh agonist binding affinity, and signal transduction through the calcium–PKC–NFAT pathway and G-protein independent PKB–GSK3 pathway.[36][37]
參考文獻
外部連結
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