CHOLINERGIC BINDING-SITES IN RAT HIPPOCAMPAL-FORMATION - PROPERTIES AND ONTOGENESIS
CHOLINERGIC BINDING-SITES IN RAT HIPPOCAMPAL-FORMATION - PROPERTIES AND ONTOGENESIS
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DOI：
10.1016/0006-8993(79)90211-7
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发表时间：
1979-01-01
期刊：
影响因子：
2.9
通讯作者：
DUDAI, Y
中科院分区：
文献类型：
--
作者：
BENBARAK, J;DUDAI, Y
大鼠的海马结构含有2种类型的膜结合胆碱能结合位点，如通过[3 H]奎宁环基二苯乙酸酯（QNB）或α-羟乙基奎宁环基二苯乙酸酯（α-H2O）的特异性结合所揭示的。[125 I]银环蛇毒素（α- Btx）。这些部位在药理学特征、对洗涤剂的敏感性和个体发育方面存在差异。主要结合位点（每个成年海马约17 pmol）具有毒蕈碱性质，并以2 × 10 - 4的结合速率结合[3 H]QNB。106 M-1 s-1，表观KD为0.4 nM。这种结合被低浓度的毒蕈碱配体取代，但不是烟碱配体。最早的结合水平的增加是在出生后第4天左右检测到的，总结合的急剧增加发生在第10和15天之间。总结合继续逐渐增加约3倍，直到约7周龄，在类似的乙酰胆碱酯酶的速率。α- BTX结合位点（每个成年海马约0.6pmol）显示烟碱特征，具有α-BTX的结合速率常数。[125 I]Btx为6 ×104 M-1 s-1，表观KD为2 nM。这些网站的个体发育明显不同于毒蕈碱位点和乙酰胆碱酯酶。绝对结合在出生后12-14天达到成熟水平，并且在出生后第1天期间每个组织蛋白的结合高于成熟时。看来，毒素结合位点的水平达到成熟值之前，在该地区的主要突触发生事件完成。
The hippocampal formation of the rat contains 2 types of membrane-bound cholinergic binding sites, as revealed by specific binding of [3H]quinuclidinyl benzilate (QNB) or of .alpha.-[125I]bungarotoxin (.alpha.-Btx). The sites differ in pharmacological profile, sensitivity to detergents and ontogenesis. The major binding site (about 17 pmol per adult hippocampus) is of a muscarinic nature, and binds [3H]QNB with an on-rate of 2 .times. 106 M-1 s-1 and an apparent KD of 0.4 nM. This binding is displaced by low concentrations of muscarinic ligands but not of nicotinic ligands. The earliest increase in binding level is detected at about day 4 postnatal and a sharp increase in total binding takes place between days 10 and 15. The total binding continues to increase gradually about 3-fold until an age of about 7 wk, at a rate resembling that of acetylcholinesterase. .alpha.-Btx-binding sites (about 0.6 pmol per adult hippocampus) display a nicotinic profile with an on-rate constant for .alpha.-[125I]Btx of 6 .times. 104 M-1 s-1 and an apparent KD of 2 nM. Ontogenesis of these sites clearly differs from that of muscarinic sites and acetylcholinesterase. Absolute binding reaches mature levels at an age of 12-14 days postnatal, and binding per tissue protein is higher during the 1st postnatal days than at maturity. It appears that the level of toxin-binding sites attains mature values before the major synaptogenetic events in the area are completed.