ACTIONS OF VERAPAMIL ON THE EXCITABILITY OF CULTURED NEURONS
ACTIONS OF VERAPAMIL ON THE EXCITABILITY OF CULTURED NEURONS
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DOI：
10.1139/y83-209
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发表时间：
1983-01-01
影响因子：
2.1
通讯作者：
SCHNEIDERMAN, JH
中科院分区：
文献类型：
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作者：
MACDONALD, JF;SCHNEIDERMAN, JH
将相对高浓度的维拉帕米（0.5-1.0 mM）应用于培养的小鼠脊髓或背根神经节神经元，可阻断Ca和Na动作电位。它们还使这些神经元去极化，并导致输入电导的电压依赖性降低（在电流箝位下测量）。L-Asp在脊髓神经元中引起的去极化和输入电导的明显减少似乎在维拉帕米的共同作用下增强。较低浓度（最大100 .mu）。维拉帕米阻断已识别的Ca动作电位，而不使神经元去极化或改变其输入电导。这种钙拮抗剂在培养的神经元中只提供有限的选择性。培养脊髓神经元的电压钳实验表明，高浓度维拉帕米（0.5 ~ 5.0 mM）可以减少向外电流（漏电流和整流）。单次应用L-Asp引起的内向电流未被维拉帕米增强，因此在电流钳下记录的增强可归因于外向电流的抑制。维拉帕米对电压依赖性向外电流（整流）的降低提高了L-Asp激活的电压依赖性向内电流的分辨率。
Applications of relatively high concentrations of verapamil (0.5-1.0 mM) to cultured mouse spinal cord or dorsal root ganglion neurons blocked both Ca and Na action potentials. They also depolarized these neurons and caused a voltage-dependent reduction of input conductance (measured under current clamp). The depolarization and apparent reduction of input conductance evoked in spinal cord neurons by L-Asp appeared to be potentiated by coapplications of verapamil. Lower concentrations (maximum 100 .mu.M) of verapamil blocked identified Ca action potentials without depolarizing neurons or changing their input conductance. This Ca antagonist provided only limited selectivity in cultured neurons. Voltage clamp of cultured spinal cord neurons demonstrated that high concentrations of verapamil (0.5-5.0 mM) can reduce outward currents (leakage and rectification). Inward currents evoked with single applications of L-Asp were not potentiated by verapamil and thus potentiations recorded under current clamp can be attributed to depression of outward currents. The reduction of voltage-dependent outward currents (rectification) by verapamil improved resolution of the voltage-dependent inward current activated by L-Asp.