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激活大麻素CB1受体(CB1Rs)通过调控多种离子通道,从而调节脊椎动物视网膜的功能。本文旨在利用膜片钳全细胞记录技术,在大鼠视网膜薄片上研究CB1Rs对神经节细胞兴奋性的作用。结果显示,在电流钳制状态下,灌流CB1R激动剂WIN55212-2(WIN,5μmol/L)对神经节细胞的自发动作电位发放频率和静息膜电位均没有显著影响。在灌流液中加入CNQX,D-APV,bicuculline和strychnine以阻断神经节细胞的兴奋性和抑制性输入,灌流5μmol/L WIN对正向电流注入(+10pA到+100pA)诱发的动作电位的频率也没有显著影响。位相分析结果显示,触发动作电位的阈值电位和触发第一个动作电位的延迟时间在加入WIN前后也没有显著改变;然而,WIN显著降低动作电位的上升和下降相速率(±dV/dtmax),而且该作用可被CB1R拮抗剂SR141716所阻断。此外,在阻断突触输入的情况下,WIN对神经节细胞的膜电位也没有显著影响。以上结果提示,激活大麻素CB1Rs通过调控诱发动作电位,从而调节大鼠视网膜神经节细胞的兴奋性。
Activation of the cannabinoid CB1 receptor (CB1Rs) regulates vertebrate retinal function by regulating multiple ion channels. The aim of this study was to investigate the effect of CB1Rs on the excitability of ganglion cells on rat retinal slices using patch-clamp whole-cell recording. The results showed that the current CB1R agonist WIN55212-2 (WIN, 5μmol / L) had no significant effect on the frequency of spontaneous action potentials and resting membrane potential of ganglion cells. CNQX, D-APV, bicuculline and strychnine were added to the perfusate to block the excitatory and inhibitory inputs of ganglion cells. The perfusion of 5μmol / L WIN induced a positive action current (+10 pA to +100 pA) The frequency also had no significant effect. Phase analysis showed that the threshold potential of the triggering action potential and the delay time of triggering the first action potential did not change significantly before and after the addition of WIN. However, WIN significantly decreased the ± dV / dtmax of the action potential, And this effect can be blocked by the CB1R antagonist SR141716. In addition, WIN also had no significant effect on the ganglion cell membrane potential in blocking synaptic input. The above results suggest that activation of cannabinoid CB1Rs regulates the excitability of rat retinal ganglion cells by regulating the action potential.