Effects of extracellular calcium and magnesium on central respiratory control in the brainstem-spinal cord of neonatal rat
Effects of extracellular calcium and magnesium on central respiratory control in the brainstem-spinal cord of neonatal rat
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DOI：
10.1016/s0006-8993(97)01476-5
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发表时间：
1998-03-09
期刊：
影响因子：
2.9
通讯作者：
Natsui, T
中科院分区：
文献类型：
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作者：
Kuwana, S;Okada, Y;Natsui, T
采用新生大鼠离体脑干-脊髓模型，观察细胞外Ca~（2+）和Mg~（2+）浓度（分别为[Ca~（2+）]（ECF）和[Mg~（2+）]（ECF））对中枢呼吸控制的影响。从C4腹根记录中枢呼吸活动。用离子敏感电极测定延髓腹侧面下[Ca~（2+）]（ECF）的深度分布。在将灌流液Ca 2+（[Ca 2 +]（CSF））从2 mM改变为0.5 mM后约1 h，[Ca 2 +]（ECF）的梯度消失，但即使在切换为无Ca 2+灌流液后2 h也没有消失。高[Ca2 +]（CSF）（4 mM）或高[Mg2 +]（CSF）（4，8 mM）降低呼吸频率（f（R）），而低[Ca2 +]（CSF）（0.5 mM）增加f（R）并增强呼吸CO2反应性。高[Ca 2 +]（CSF）和低[Mg 2 +]（CSF）（0.5 mM）扰乱了呼吸节律和模式，高CO2可显着恢复这些节律和模式。用穿孔膜片记录证实了高[Ca~（2+）]（ECF）对延髓神经元电活动的抑制作用和低[Ca~（2+）]（ECF）对延髓神经元电活动的刺激作用。这些结果表明，[Ca 2 +]（ECF）和[Mg 2 +]（ECF）通过调节神经元表面电位，跨膜Ca 2+内流，Ca 2+敏感的阳离子通道门控和突触传递决定呼吸神经元网络的兴奋性。此外，这些行动中的一些似乎是拮抗CO2/H+。(C)1998年Elsevier Science B.V.
The influence of extracellular Ca2+ and Mg2+ concentrations ([Ca2+](ECF) and [Mg2+](ECF), respectively) on central respiratory control was analyzed using the isolated brainstem-spinal cord of the neonatal rat. Central respiratory activity was recorded from the C4 ventral roots. The depth profile of [Ca2+](ECF),, below the ventral medullary surface was measured with ion-sensitive electrodes. The gradient in [Ca2+](ECF) disappeared about 1 h after changing superfusate Ca2+ ([Ca2+](CSF)) from 2 to 0.5 mM, but not even in 2 h after switching to Ca2+-free superfusate. High [Ca2+](CSF) (4 mM) or high [Mg2+](CSF) (4, 8 mM) decreased respiratory frequency (f(R)), whereas low [Ca2+](CSF) (0.5 mM) increased f(R) and augmented the respiratory CO2 responsiveness. High [Ca2+](CSF) as well as low [Mg2+](CSF) (0.5 mM) disturbed respiratory rhythm and pattern, which were markedly restored by high CO2. The depressing effect of high [Ca2+](ECF) and the stimulating effect of low [Ca2+](ECF) On the medullary neuronal activity were confirmed by perforated patch recordings. These results suggest that [Ca2+](ECF) and [Mg2+](ECF) determine the excitability of the respiratory neuron network by modulating the neuronal surface potential, transmembrane Ca2+ influx, Ca2+-sensitive cation channel gating, and synaptic transmission. Furthermore, some of these actions appear to be antagonized by CO2/H+. (C) 1998 Elsevier Science B.V.