匹诺塞林对体外共培养海兔SN/L7神经元电生理活动的作用

目的研究匹诺塞林(PNCB)对海兔神经元共培养体系(SN/L7)的电生理效应,探讨可能的作用机制。方法体外共培养海兔(aplysia)的感觉神经元(SN)和运动神经元(L7),使其互相接触形成突触连接。细胞培养至d 5,给予不同浓度的PNCB刺激,考察药物对SN/L7兴奋性突触后电位(EPSP)的影响,随后撤去药物,观察EPSP的恢复情况。另取细胞,在PNCB孵育后加入0.005 mmol.L-15-羟色胺(5-HT),观察SN/L7对5-HT的反应性的变化。结果 PNCB作用5 min,使SN/L7的EPSP幅值降低。药物浓度低于0.1 mmol.L-1时,作用强度与药物剂量呈负线性关系(r>0.995),在0.1～0.4 mmol.L-1的浓度范围内,作用强度与药物剂量呈正线性关系(r>0.998);撤去药物后,SN/L7的EPSP幅值可恢复至初始值。PNCB使SN/L7对5-HT的反应性消失,撤去药物后,该反应性得以恢复。结论 PNCB可逆地抑制体外共培养的海兔SN/L7神经元突触的兴奋性传导,并可逆地抑制SN/L7对5-HT的反应性。这一效应可能与突触后膜的谷氨酸受体有关。

Electrophysiological effects of pinocembrin on Aplysia SN/L7 co-cultures

Aim To study the neural electrophysiological effects of pinocembrin(PNCB) on Aplysia sensory/motor neuron co-cultures.Methods Isolated Aplysia sensory neuron(SN) and motor neuron(L7) were co-cultured for up to 5 days.At Day 5,SN/L7 was incubated with PNCB for 5 min.Excited postsynaptic potential(EPSP) was recorded immediately before and after PNCB treatment,as well as 1 h and 24 h after the removal of PNCB from the culture dish.0.005 mmol·L-1 serotonin was added to culture dishes in another set of experiment with or without the removal of PNCB,to examine the possible effect of PNCB on serotonin(5-HT) induced synaptic facilitation in sensorimotor connections.Results PNCB incubation effectively reduced the EPSP amplitude of Aplysia SN/L7 co-cultures.Linear relationship between PNCB concentration and EPSP amplitude could be established when PNCB concentration was between 0.01~0.1 mmol·L-1 or 0.1~0.4 mmol·L-1,respectively,going in opposite directions,i.e.the least repressing effect was observed when PNCB concentration was 0.1 mmol·L-1.Also observed was that incubation with 0.01 mmol·L-1 PNCB inhibited 5-HT induced synaptic facilitation.However,no effect was detected when 5-HT was applied after removal of PNCB.Conclusions PNCB reversibly represses the signal transduction at SN/L7 synapses,and reversibly inhibits 5-HT induced SN/L7 synaptic facilitation.Possible mechanism can be attributed to the complicated effects of PNCB towards pre-and post-synaptic ion channels.