Effects of divalent cations on Schaffer collateral axon function.
Effects of divalent cations on Schaffer collateral axon function.
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DOI：
10.1007/s00221-020-06026-z
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发表时间：
2021-10
影响因子：
2
通讯作者：
Grover LM
中科院分区：
文献类型：
--
作者：
Owen B;Woode F;Grover LM
以前，我们报告说，远端谢弗侧支经历双相变化的兴奋性在高频刺激（HFS），与早期的超兴奋期，随后兴奋性抑郁期。细胞外二价阳离子钙和镁可以调节神经组织的膜兴奋性。因此，我们假设改变细胞外钙和镁的浓度会改变双相兴奋性的变化。我们测试了这一假设，通过记录在100 Hz HFS在人工脑脊髓液（ACSF）含有正常和改变浓度的细胞外二价阳离子的海马区CA 1区辐射层的远端谢弗侧支纤维凌空。我们的正常ACSF含有2.0 mM钙和2.0 mM镁。我们检查了四种改变二价阳离子浓度的溶液：1）高钙/低镁（3.8 mM/0.2 mM），2）低钙/高镁（0.2 mM/3.8 mM），3）高钙/正常镁（3.8 mM/2.0 mM），或4）正常钙/高镁（2.0 mM/10.0 mM），并评估了对Schaffer侧支反应的影响。增加或减少细胞外钙增强或减少（分别）早期的高兴奋期，而增加细胞外镁减少了后来的兴奋性抑郁症。由于这些结果可能通过改变通过电压门控钙（CaV）通道的钙内流来解释，我们测试了CaV阻断剂（ω-agatoxin IVA，ω-conotoxin-GVIA，镉），但在HFS期间未观察到对反应的影响。改变的二价阳离子浓度的一些影响可以通过改变膜表面电荷来解释。虽然这一机制不能完全解释我们的发现，钙内流通过CaV通道是不需要的。
Previously, we reported that distal Schaffer collaterals undergo biphasic changes in excitability during high-frequency stimulation (HFS), with an early hyper-excitability period followed by an excitability depression period. The extracellular divalent cations calcium and magnesium can regulate membrane excitability in neuronal tissue. Therefore, we hypothesized that altering the concentrations of extracellular calcium and magnesium would alter the biphasic excitability changes. We tested this hypothesis by recording distal Schaffer collateral fiber volleys in stratum radiatum of hippocampal area CA1 during 100 Hz HFS in artificial cerebral spinal fluid (ACSF) containing normal and altered concentrations of extracellular divalent cations. Our normal ACSF contained 2.0 mM calcium and 2.0 mM magnesium. We examined four solutions with altered divalent cation concentrations: 1) high-calcium/low-magnesium (3.8 mM/0.2 mM), 2) low-calcium/high-magnesium (0.2 mM/3.8 mM), 3) high-calcium/normal-magnesium (3.8 mM/2.0 mM), or 4) normal-calcium/high-magnesium (2.0 mM/10.0 mM), and assessed the effects on Schaffer collateral responses. Increasing or decreasing extracellular calcium enhanced or reduced (respectively) the early hyper-excitable period whereas increasing extracellular magnesium reduced the later excitability depression. Because these results might be explained by altered calcium influx through voltage-gated calcium (CaV) channels, we tested CaV blockers (ω–agatoxin IVA, ω-conotoxin-GVIA, cadmium), but observed no effects on responses during HFS. Some of the effects of altered divalent cation concentration may be explained by altered membrane surface charge. Although this mechanism does not completely explain our findings, calcium influx through CaV channels is not required.
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影响因子：
3.8
作者：
Bennett, E;Urcan, MS;Levinson, SR
通讯作者：
Levinson, SR
DOI：
10.1073/pnas.052151299
发表时间：
2002-04-30
影响因子：
11.1
作者：
Shepherd, GMG;Raastad, M;Andersen, P
通讯作者：
Andersen, P
影响因子：
5.5
作者：
DODGE, FA;RAHAMIMO.R
通讯作者：
RAHAMIMO.R
影响因子：
2.5
作者：
MODY, I;LAMBERT, JDC;HEINEMANN, U
通讯作者：
HEINEMANN, U
影响因子：
5.5
作者：
HANCK, DA;SHEETS, MF
通讯作者：
SHEETS, MF