Aguayo L G, White G
Section of Electrophysiology, National Institute on Alcohol Abuse and Alcoholism, Rockville, MD 20852.
Brain Res. 1992 Jan 20;570(1-2):61-7. doi: 10.1016/0006-8993(92)90564-p.
We have investigated the effects of nerve growth factor (NGF, 2.5 ng/ml for 1-2 weeks) on enriched adult rat dorsal root ganglion (DRG) neurons maintained in cell culture in defined media. Whole-cell recordings in cells cultured in the absence and presence of NGF revealed no significant difference in resting membrane potential and input resistance. However, the threshold for spike generation was significantly lower in untreated cells than in treated cells; -25 +/- 1.1 mV vs -19 +/- 2.2 mV, respectively. The sensitivity of the Na+ spike to tetrodotoxin (TTX, 1 microM) was different in cells cultured in the absence or presence of NGF. For example, spikes were abolished by TTX in 100% of untreated cells, while in NGF-treated cells the spike was abolished in only 41% of the neurons. Chemosensitivity of DRG neurons was also different in the absence and presence of NGF. For example, the percent of neurons in which a current activated by 8-methyl-N-vanillyl-6-nonenamide (capsaicin, 500 nM) was detected, increased from 18% in untreated cells to 55% in NGF-treated cells. NGF did not influence the number of cells surviving. The results indicate that NGF can regulate TTX and capsaicin sensitivity in these adult rat sensory neurons. Our experimental protocol indicates that this effect is not mediated by a factor in the serum or released from non-neuronal cells.
我们研究了神经生长因子（NGF，2.5 ng/ml，作用1 - 2周）对在限定培养基中进行细胞培养的成年大鼠背根神经节（DRG）富集神经元的影响。在有无NGF培养的细胞中进行全细胞膜片钳记录发现，静息膜电位和输入电阻无显著差异。然而，未处理细胞产生动作电位的阈值显著低于处理过的细胞；分别为-25±1.1 mV和-19±2.2 mV。在有无NGF培养的细胞中，Na⁺动作电位对河豚毒素（TTX，1 μM）的敏感性不同。例如，在100%的未处理细胞中，TTX可消除动作电位，而在NGF处理的细胞中，只有41%的神经元的动作电位被消除。在有无NGF的情况下，DRG神经元的化学敏感性也不同。例如，检测到由8 - 甲基 - N - 香草基 - 6 - 壬酰胺（辣椒素，500 nM）激活电流的神经元百分比，从未处理细胞中的18%增加到NGF处理细胞中的55%。NGF不影响存活细胞的数量。结果表明，NGF可调节成年大鼠这些感觉神经元对TTX和辣椒素的敏感性。我们的实验方案表明，这种效应不是由血清中的因子或非神经元细胞释放的因子介导的。
