Nicotinic-agonist stimulated (86)Rb(+) efflux and [(3)H]epibatidine binding of mice differing in beta2 genotype.
Nicotinic-agonist stimulated (86)Rb(+) efflux and [(3)H]epibatidine binding of mice differing in beta2 genotype.
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烟碱激动剂刺激β2基因型不同的小鼠的(86)Rb(·)流出和[(3)H]epibatidine结合。
DOI：
10.1016/s0028-3908(00)00115-5
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发表时间：
2000
影响因子：
4.7
通讯作者：
Collins,AC
中科院分区：
文献类型：
--
作者：
Marks,MJ;Stitzel,JA;Grady,SR;Picciotto,MR;Changeux,JP;Collins,AC
在β2亚基表达不同的小鼠的12个脑区中测量烟碱乙酰胆碱受体功能和结合。通过在线检测在测量两种不同烟碱反应的条件下刺激的~（86）Rb ~+外排来测量功能：（1）用10 μM尼古丁刺激，这种反应对拮抗剂二氢-β-赤藓定（DHβE）的抑制相对敏感;（2）在2 μM DHβE存在下，用10 μM地棘蛙素刺激，这种反应对DHβE的抑制作用相对抵抗。β2亚基的缺失极大地减少了每个大脑区域中DHβ E敏感性和耐药性86 Rb+的外排，并基本上消除了大脑皮质和丘脑等区域的活性。然而，在嗅球和下丘等区域观察到残留活性。[3 H]在允许估计高和低亲和力位点的条件下测量地棘蛙素结合。对烟碱激动剂野靛碱抑制敏感的高亲和力位点在每个区域几乎都被β2无效突变消除。相反，在β2无效突变体中，仅消除了对野靛碱抑制不敏感的高亲和力位点的子集，表明受体异质性。类似地，低亲和力[3 H]地棘蛙素结合是异质的，因为一部分位点需要β2亚基。许多剩余的位点对α-银环蛇毒素的抑制敏感，表明低亲和力[3 H]地棘蛙素结合的一个子集是α7* 亚型。在12个脑区中观察到明显的区域差异。这些研究证实了含β2受体在介导多种不同功能和作为几个可识别结合位点的组分中的重要作用。
Nicotinic acetylcholine receptor function and binding was measured in 12 brain regions from mice differing in β2 subunit expression. Function was measured by on-line detection of86Rb+efflux stimulated under conditions that measure two pharmacologically distinct nicotinic responses: (1) stimulation with 10 μM nicotine, a response that is relatively sensitive to inhibition by the antagonist, dihydro-β-erythroidine (DHβE); and (2) stimulation with 10 μM epibatidine in the presence of 2 μM DHβE, a response that is relatively resistant to inhibition by DHβE. Deletion of the β2 subunit profoundly reduced both DHβE-sensitive and -resistant86Rb+efflux in each brain region and essentially eliminated activity in regions such as cerebral cortex and thalamus. However, residual activity was observed in regions such as olfactory bulbs and inferior colliculus. [3H]Epibatidine binding was measured under conditions that allow estimation of both high- and low-affinity sites. High-affinity sites sensitive to inhibition by the nicotinic agonist, cytisine, were virtually eliminated in every region by the β2 null mutation. In contrast, only a subset of the high-affinity sites insensitive to inhibition by cytisine were eliminated in β2 null mutants, suggesting receptor heterogeniety. Similarly, low affinity [3H]epibatidine binding was heterogeneous in that a fraction of the sites required the β2 subunit. Many remaining sites were sensitive to inhibition by α-bungarotoxin indicating that a subset of the low affinity [3H]epibatidine binding are of the α7* subtype. Distinct regional variation was observed among the 12 brain regions. These studies confirm important roles for β2-containing receptors in mediating pharmacologically distinct functions and as components of several identifiable binding sites.