关键词: 克氏原螯虾, 腹六节, 光敏神经元, 适应, 中枢启动反射环路, 神经元潜能, 神经元机能消亡

Abstract: Crayfish A6 ganglion responses to 520nm monochrome illumination with an increase in discharging frequency, which shows an obvious adaptation after 2min. During the adaptation period the responses to test-illuminations decline. This characteristic response can not be suppressed by extracellular high [Mg²⁺], but be accelerated by it alternatively. Extracellular high [Ca²⁺] can accelerate the adaptation. It seems there is no chemical synapses involved in the adaptation. Extracellular low [Na⁺] can delay the time course of adaptation, and the effect of low [Na⁺] can be diminished by the extracellular high [Ca²⁺]. Also, we did not observe transportation of the characteristic response across hypopharyngeal ganglion. This suggested a central reflex model that was initiated by the photosensitive neuron in crayfish CNS perhaps. Statistics from 239 samples imply a possibility during development course of crayfish: the neuron reserves photosensitive potential to response to illumination; or gradualy eliminates its function in adult stage.

Key words: Procamburus clarkii, A6 ganglion, CPR, photosensitive neuron, adaptation, centrally initiated reflex model, potential of neuron, elimination of function of neuron