van der Valk J B, Vijverberg H P
Research Institute of Toxicology, University of Utrecht, The Netherlands.
Brain Res. 1991 Sep 20;559(2):220-4. doi: 10.1016/0006-8993(91)90005-g.
Possible effects of tetanus toxin (TeTox) on voltage-activated Ca2+ channels of the mouse neuroblastoma cell line N1E-115 and of the neuroblastoma x glioma hybrid cell line NG108-15 have been investigated using the whole-cell voltage clamp technique. Similar to N1E-115 cells, differentiated NG108-15 cells express transient (T-type) as well as long-lasting (L-type) Ca2+ channels. Using various treatment protocols N1E-115 and NG108-15 cells were exposed to TeTox externally and by internal dialysis. In the cells treated with TeTox normal Ca2+ channel activity was present, as measured by the voltage-activated Ba2+ currents under voltage clamp conditions. In addition, intracellular microelectrode recordings showed that TeTox did not block the Ca2+ action potential in N1E-115 cells. It is concluded that TeTox, in contrast to previously reported results, does not affect voltage-activated T- and L-type Ca2+ channels in cultured neuronal cell lines. The results also indicate that Ca2+ channel block is unlikely to be an explanation for the block of neurotransmitter release by TeTox in vivo.
利用全细胞膜片钳技术，研究了破伤风毒素（TeTox）对小鼠神经母细胞瘤细胞系N1E - 115和神经母细胞瘤 - 胶质瘤杂交细胞系NG108 - 15电压门控性Ca2 +通道的可能影响。与N1E - 115细胞相似，分化的NG108 - 15细胞表达瞬时（T型）和长效（L型）Ca2 +通道。采用多种处理方案，将N1E - 115和NG108 - 15细胞分别进行细胞外和通过内部透析暴露于TeTox。在用TeTox处理的细胞中，通过电压钳制条件下的电压门控性Ba2 +电流测量，存在正常的Ca2 +通道活性。此外，细胞内微电极记录表明，TeTox不会阻断N1E - 115细胞中的Ca2 +动作电位。得出的结论是，与先前报道的结果相反，TeTox不会影响培养的神经元细胞系中的电压门控性T型和L型Ca2 +通道。结果还表明，Ca2 +通道阻断不太可能是TeTox在体内阻断神经递质释放的原因。
