Calcium changes in isolated peptidergic neurons during activation by a cAMP analog.
Calcium changes in isolated peptidergic neurons during activation by a cAMP analog.
复制标题
在 cAMP 类似物激活过程中，分离的肽能神经元中的钙发生变化。
DOI：
10.1016/0006-8993(88)90906-7
复制
发表时间：
1988
期刊：
影响因子：
2.9
通讯作者：
Strumwasser,F
中科院分区：
文献类型：
--
作者：
Woolum,JC;Strumwasser,F
完整海兔的袋细胞神经元通过产生约 30 分钟的动作电位放电后控制产卵，在此期间释放神经肽产卵激素。先前的研究表明cAMP、蛋白磷酸化和Ca2+参与了后放电的机制。通过 cAMP 类似物处理，可以在解离的袋细胞中产生自发放电和后放电。虽然药理学证据表明袋细胞的动作电位存在大量钙，但尚未出现通过测量 (Ca2+)i 的直接证据，也没有检查 cAMP 激活期间的 Ca 缓冲。我们的研究旨在使用金属时效指示剂砷那唑 III 测量贴壁细胞培养物中分离的袋细胞的 (Ca2+) 变化，同时记录细胞膜上的电压。研究发现，单个诱导动作电位导致 (Ca2+)i 的上升可以忽略不计，而 35 个尖峰序列会导致显着上升（约 3 × 10−4 吸光度单位）。增加外部 (Ca2+) 会增强动作电位和 Ca2+ 信号，而钴离子会阻止动作电位和 (Ca2+)i 的上升。通过 TEA (50 mM) 或 8-苯甲硫基 cAMP (8-BTcAMP; 0.5 mM) 延长尖峰持续时间可增强 Ca2+ 内流，并允许检测单尖峰导致的 Ca2+ 瞬态。在 TEA 或 8-BTcAMP 中的自发动作电位组中，(Ca2+)i 增加，但袋细胞的 Ca2+ 缓冲系统能够在大约 20 秒的半时间内恢复 Ca2+ 水平。 cAMP 似乎不会改变细胞中 Ca2+ 缓冲系统处理由于其诱导的自发活动而产生的额外 Ca2+ 流入的能力。
The bag cell neurons of intactAplysiacontrol egg-laying by producing an approximately 30 min afterdischarge of action potentials, during which the neuropeptide egg-laying hormone is released. Previous studies have shown that cAMP, protein phosphorylation and Ca2+are involved in the mechanisms of the afterdischarge. Spontaneous discharge and afterdischarge can be produced in dissociated bag cells by treatment with cAMP analogs. While pharmacological evidence exists for a large calcium cn the action potentials of bag cells, direct evidence by measuring (Ca2+)ihas not appeared, nor has Ca-buffering during cAMP activation been examined. Our studies were directed at measuring (Ca2+)ichanges in isolated bag cells in attached cell culture using the metallochronic indicator, arsenazo III, simultaneously with voltage recordings across the cell membrene. It was found that a single induced action potential causes a negligible rise in (Ca2+)iwhile a train of 35 spikes causes a significant rise (about 3 × 10−4absorbance units). Increasing external (Ca2+) enhances the action potential and Ca2+signal while cobaltous ions block both the action potentials and the rise in (Ca2+)i. Lengthening the duration of spikes by TEA (50 mM) or 8-benzylthio cAMP (8-BTcAMP; 0.5 mM) enhances Ca2+influx and allows the detection of Ca2+transients due to single spikes. During spontaneous groups of action potentials in either TEA or 8-BTcAMP, (Ca2+)iincreases but the bag cell's Ca-buffering systems are able to restore the Ca2+levels with a half-time of about 20 s. cAMP did not appear to alter the ability of the Ca-buffering systems in the cell to handle the extra load of Ca2+influx due to the spontaneous activity that it induces.