Dopamine receptor regulation of Ca2+ levels in individual isolated nerve terminals from rat striatum: comparison of presynaptic D1-like and D2-like receptors.
Dopamine receptor regulation of Ca2+ levels in individual isolated nerve terminals from rat striatum: comparison of presynaptic D1-like and D2-like receptors.
复制标题
多巴胺受体对大鼠纹状体单个分离神经末梢 Ca2 水平的调节：突触前 D1 样和 D2 样受体的比较。
DOI：
10.1111/j.1471-4159.2006.03901.x
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Nichols,RobertA
中科院分区：
文献类型：
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作者：
Wu,Jianlin;Dougherty,JohnJ;Nichols,RobertA
我们直接观察了激活突触前D1样和D2样多巴胺受体对大鼠纹状体分离的神经末梢（突触体）中Ca 2+水平的影响。选择性D1样受体激动剂R-（+）-SKF 81297和选择性D2样受体激动剂（-）-quinpirole可诱导单个纹状体突触体不同亚群中Ca 2+水平升高。SKF 81297和喹吡罗诱导的效应分别被D1样受体拮抗剂R-（+）-SCH 23390和D2样受体拮抗剂（-）-舒必利阻断。阻断电压门控钙通道或钠通道后，SKF 81297或喹吡罗诱导的Ca 2+升高受到抑制。在一个较大的子集的突触体，喹吡罗降低基线Ca 2+。喹吡罗还抑制藜芦碱诱导的突触体内Ca 2+水平升高。免疫组化证实D1、D5、D2和D3受体在突触前表达，而D4受体无表达。表达D1、D5、D2或D3的纹状体神经末梢的神经递质表型阵列因每个受体亚型而异。这些结果表明，突触前D1样和D2样受体通过Na+通道介导的膜去极化诱导不同神经末梢亚群中的Ca 2+水平增加，这反过来又诱导电压门控钙通道的开放。D2样受体还减少了突触体不同但更大子集中的神经末梢Ca 2+，这与纹状体中多巴胺的主要突触前作用是抑制性的一致。
We have directly observed the effects of activating presynaptic D1‐like and D2‐like dopamine receptors on Ca2+levels in isolated nerve terminals (synaptosomes) from rat striatum. R‐(+)‐SKF81297, a selective D1‐like receptor agonist, and (–)‐quinpirole, a selective D2‐like receptor agonist, induced increases in Ca2+levels in different subsets of individual striatal synaptosomes. The SKF81297‐ and quinpirole‐induced effects were blocked by R‐(+)‐SCH23390, a D1‐like receptor antagonist, and (–)‐sulpiride, a D2‐like receptor antagonist, respectively. SKF81297‐ or quinpirole‐induced Ca2+increases were inhibited following blockade of voltage‐gated calcium channels or sodium channels. In a larger subset of synaptosomes, quinpirole decreased baseline Ca2+. Quinpirole also inhibited veratridine‐induced increases in intrasynaptosomal Ca2+level. Immunostaining confirmed the presynaptic expression of D1, D5, D2and D3receptors, but not D4receptors. The array of neurotransmitter phenotypes of the striatal nerve endings expressing D1, D5, D2or D3varied for each receptor subtype. These results suggest that presynaptic D1‐like and D2‐like receptors induce increases in Ca2+levels in different subsets of nerve terminals via Na+channel‐mediated membrane depolarization, which, in turn, induces the opening of voltage‐gated calcium channels. D2‐like receptors also reduce nerve terminal Ca2+in a different but larger subset of synaptosomes, consistent with the predominant presynaptic action of dopamine in the striatum being inhibitory.