Optical recording of the synaptic functions of the frog lumbar sympathetic ganglia using voltage-sensitive dyes.

在制备牛蛙腰交感神经节的过程中，采用电压敏感的merocyanine-rhodanine染料（NK2761）和多元件光电二极管阵列，采用多位点电活动光学记录技术监测电刺激下的神经反应。在制备过程中，利用吸电极对神经进行去极化（正）方电流脉冲刺激，同时记录了多个连续位点的电压相关吸光变化。对神经节细胞突触后轴突的反向刺激（后刺激）所激发的光信号表现出相对简单的形状，有一个尖峰，然后是一个下突，这可能分别反映了神经节细胞的动作电位和后超极化。另一方面，对突触前纤维（前刺激）进行正交刺激所诱发的光信号也呈尖状，但形状更为复杂，且常出现双峰信号，说明突触前神经元和突触后神经元的成分在诱发的光信号中是叠加的。采用低ca ^<2+>的林格溶液或d-管curarine （d-Tc）抑制突触传递，将预刺激引起的光信号依次分离为突触前和突触后组分。光信号的突触前组分能够抵抗突触传递的抑制，并被认为依赖于外部Ca^<2+>。

In the preparations of the lumbar sympathetic ganglion dissected from bullfrogs, the neural responses to electrical stimulation were monitored by using multiple-site optical recording of electrical activity,with a voltage- sensitive merocyanine-rhodanine dye (NK2761) and a multiple element photodiode array. Voltage-related absorbance changes evoked by nerve stimulation with depolarizing (positive) square current pulses using a suction electrode were recorded simultaneously from many contiguous loci in the preparation.The optical signals, evoked by the antidromic stimulation for the post- synaptic axons of the ganglion cells (post-stimulation), exhibited a relatively simple shape with a sharp spike followed by the undershoot, which is likely to reflect the action potential and the after-hyperpolarization of the ganglion cells respectively. On the other hand, the optical signals, evoked by orthodromic stimulation applied to the pre-synaptic fibers (pre-stimulation), were also spike-like but more complex in shape, and the double-peaked signals were often observed, suggesting that the component from pre-synaptic neurons and that from post-synaptic neurons were superimposed in the evoked optical signals.Using a low-Ca^<2+> Ringer solution or d-tubocurarine (d-Tc) to suppress the synaptic transmission, the optical signals evoked by pre-stimulation were successively separated into pre-synaptic and post-synaptic components. The pre- synaptic component of the optical signals was resistant to the suppression of the synaptic transmission, and was suggested to be dependent on the external Ca^<2+>.