Brain synaptosomes display a diadenosine tetraphosphate (Ap4A)‐mediated Ca2+ influx distinct from ATP‐mediated influx
Brain synaptosomes display a diadenosine tetraphosphate (Ap4A)‐mediated Ca2+ influx distinct from ATP‐mediated influx
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脑突触体表现出四磷酸二腺苷 (Ap4A) 介导的 Ca2+ 流入，与 ATP 介导的流入不同
DOI：
10.1002/(sici)1097-4547(19960601)44:5
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发表时间：
1996
影响因子：
4.2
通讯作者：
A. Nordone
中科院分区：
文献类型：
--
作者：
E. Pivorun;A. Nordone
比较Ap4A和ATP对鹿鼠脑突触体内钙水平的影响的研究表明，这两种配体都能诱导细胞外钙的快速内流。16 7μM AP4A诱发的钙离子谱呈“尖峰状”(下降到基线的半衰期为19.1±1.2秒)，而三磷酸腺苷则呈逐渐下降的趋势(104.0±7.4秒)。DIDS(4-4‘-二异硫氰基-2，2’-二磺酸二苯乙烯)和苏拉明预先孵育仅改变ATP诱导的钙离子分布。交叉脱敏研究表明，预先应用ATP对Ap4A诱导的钙内流无显著影响，而预先应用Ap4A对ATP诱导的钙内流无明显影响。这些结果表明，细胞外Ap4A和ATP引起不同的突触体内钙内流，提示这两个核苷酸可能与不同的嘌呤受体亚类或嘌呤受体-效应复合体相互作用。同时给予突触体去极化和Ap4A，或去极化和三磷酸腺苷，对钙离子内流产生相加效应。用异搏定预先孵育可在不改变配体引起的钙离子流量的情况下抵消去极化的作用。这些结果表明，Ap4A和ATP配基门控通道的存在可能是神经元活动的调节器。©1996 Wiley-Liss，Inc.
Studies undertaken to compare the effects of Ap4A and ATP on altering intrasynaptosomal Ca2+ levels from deermouse brain reveal that both ligands induce a rapid influx of extracellular Ca2+. The Ca2+ profile elicited by 167 μM Ap4A is “spike‐like” (half‐time for decline to baseline, 19.1 ± 1.2 sec), in contrast to the gradual decline observed with ATP (104.0 ± 7.4 sec). DIDS (4‐4′‐diisothiocyano‐2,2′‐disulfonic acid stilbene) and suramin preincubation alter only the ATP‐induced Ca2+ profile. Cross‐desensitization studies indicate that prior application of ATP does not significantly affect the Ca2+ influx elicited by Ap4A, and that prior application of Ap4A does not affect the Ca2+ influx elicited by ATP. These results demonstrate that extracellular Ap4A and ATP elicit distinct intrasynaptosomal Ca2+ influx profiles, and suggest that these two nucleotides may be interacting with distinct purinoceptor subclasses or purinoceptor‐effector complexes. Subjecting the synaptosomes simultaneously to depolarization and Ap4A, or to depolarization and ATP, induces an additive effect on Ca2+ influx. Preincubation with verapamil negates the effects of depolarization without modifying the ligand‐elicited Ca2+ fluxes. These results indicate the presence of Ap4A and ATP ligand‐gated channels that may function as modulators of neuronal activity. © 1996 Wiley‐Liss, Inc.
可兴奋细胞中 ATP 激活的通道。
DOI：
10.1007/978-1-4615-7305-0_5
发表时间：
1990
期刊：
Ion channels
影响因子：
--
作者：
Bean,BP;Friel,DD
通讯作者：
Friel,DD
细胞外 ATP 增加大鼠腮腺腺泡细胞中的游离胞质钙。
DOI：
--
发表时间：
1988
期刊：
The Biochemical journal
影响因子：
--
作者：
McMillian,MK;Soltoff,SP;Lechleiter,JD;Cantley,LC;Talamo,BR
通讯作者：
Talamo,BR
测定培养的哺乳动物细胞中的二腺苷 5,5,-P1,P4-四磷酸水平。
影响因子：
2.9
作者：
Baker,JC;Jacobson,MK
通讯作者：
Jacobson,MK