Bagnoli P, Brunelli M, Magni F, Pellegrino M
Arch Ital Biol. 1975 Feb;113(1):21-43.
A single neuron, located in the center of each segmental ganglion of H. medicinalis is antidromically activated by electrical stimulation of the ventral cord anteriorly and posteriorly to the ganglion, at the same threshold as the fast conducting system (FCS) and with a latency equal to the FCS conduction time. This neuron is activated trans-synaptically by tactile and photic stimulation of the skin and by stimulation of high-threshold fibres running along the cord. A spike evoked by intracellular stimulation of this neuron propagates along the FCS. Intracellular staining shows that this neuron sends two axonal branches in the anterior and posterior median connectives. Direct electrical stimulation of touch cells (T cells), as well as mechanical stimulation of the skin, lowers the threshold of and may eventually fire, the FCS neurons, not only at the level of the ganglion to which they belong, but also at the level of the neighbouring ganglia. This effect is mediated by bilateral pathwasy located in the lateral connectives. It is concluded that the FCS consists of a chain of single neurons, located in each ganglion and electrotonically coupled to each other. Touch cells project with excitatory synapses on the FCS neurons.
位于药用海兔每节段神经节中心的单个神经元，在神经节前和节后对腹神经索进行电刺激时会被逆向激活，其阈值与快速传导系统（FCS）相同，潜伏期与FCS传导时间相等。该神经元通过对皮肤的触觉和光刺激以及对沿神经索走行的高阈值纤维的刺激进行跨突触激活。通过对该神经元进行细胞内刺激诱发的一个峰电位沿FCS传播。细胞内染色显示，该神经元在前、后正中连合中发出两个轴突分支。对触觉细胞（T细胞）进行直接电刺激以及对皮肤进行机械刺激，不仅会降低其所属神经节水平的FCS神经元的阈值，还会降低相邻神经节水平的FCS神经元的阈值，并最终可能使其放电。这种效应由位于外侧连合中的双侧通路介导。得出的结论是，FCS由位于每个神经节中且相互电耦合的单个神经元链组成。触觉细胞通过兴奋性突触投射到FCS神经元上。
