He-Ne激光对大鼠离体颈上神经节后神经元膜电导的影响

应用细胞内生物电记录技术 ,观测不同功率、不同照射时间的 He- Ne激光 (脉冲频率 1Hz)对大鼠离体颈上神经节后神经元快兴奋性突触后电位 (f- EPSP)期间膜电导的影响。功率密度为 2 m W/ cm2 的 He- Ne激光在照射初期 (1min～ 2 min)引起快兴奋性突触后电位 (f- EPSP)幅值增大 ,同时膜电导增大 ;而在激光照射后期 (后 3m in～8m in)引起节后神经元膜电导减少。功率密度为 5 m W/ cm2 的 He- Ne激光照射期膜电导无明显变化 .结果表明 :功率密度为 2 m W/ cm2 的 He- Ne激光照射初期引起膜电导 (Gl=34.6± 5 .4 n S)较照射前 (Gf=2 6 .8± 6 .2 n S)有明显增大 (P<0 .0 5 ) ,照射后期膜电导减少。提示 :He- Ne激光照射可能是通过两时相效应改变节后神经元膜电导来影响交感神经节内兴奋传递过程。这可能是低功率激光对神经细胞的一种作用机制。

Effect of He-Ne Laser on Membrane Conductance of Postganglionic Neurons in the Isolated Rat Superior Cervical Ganglia

The effects of He Ne laser with wavelength 632.8nm on membrane conductance of postganglionic neurons of the isolated rat superior cervical ganglia were investigated by means of intracellular recording techniques. The neurons with stable fast excitatory postsynaptic potential(f EPSP) were irradiated by the laser with power densities of 2mW/cm 2 and 5mW/cm 2, pulse frequency of 1HZ. Irradiated by the 2mW/cm 2 laser, membrane conductance increased from 26.8±6.2nS before irradiation to 34.6±5.4nS at the first 1min~2 min(P<0.05).Membrane conductance decreased for 3min~8 min later. But for the 5mW/cm 2 laser irradiation, membrane conductance decreased during the irradiating periods. The results indicated that there could be the second order phases in the interaction of He Ne laser with neurons and the He Ne laser biological effect on the fast excitatory synaptic transmission may be influenced by membrane conductance changed by laser irradiation.