皮质醇对牛蛙交感神经节B细胞电生理特性及突触传递的快速作用

Rapid Effects of Hydrocortisone on the Electrophysiological Properties and Synaptic Tranmission of B Neurons in Bullfrog Sympathetic Ganglia

在离体灌流的７２只牛蛙交感神经节标本上，电刺激节前纤维，细胞内记录Ｂ细胞的电活动。观察皮质醇对Ｂ细胞的电生理学特性和突触传递的快速作用。２９个Ｂ细胞，给予１μｍｏｌ／Ｌ皮质醇后，静息电位、动作电位振幅和超射值及膜时间常数均无明显变化，但输入阻抗增加和膜电容减少却变化明显；电刺激节前纤维，细胞内记录１８３个Ｂ细胞的动作电位，给予皮质醇０５～３ｍｉｎ，部分Ｂ细胞的突触传递发生脱漏甚至完全阻断，有明显的量效关系。上述结果提示，皮质醇对牛蛙交感神经节Ｂ细胞的突触传递具有快速阻断作用，这种作用不经基因组机制，可能是皮质醇通过Ｎ受体介导而引起。也提示在应激反应时，皮质醇可能快速调制交感神经系统的功能。

We reported here the rapid effects of hydrocortisone 21 hemisuccinate (F suc) on the electrophysiological properties and the synaptic transmission of B neurons in the bullfrog sympathetic ganglia (BFSG) with intracellular recording technique in vitro. The main results were as follows: (1) The passive membrane properties of 29 B neurons were studies. F suc caused the raising of the input resistance and reducing of membrane capacitance without any changes in the membrane time constant, resting potential, amplitude and overshoot of the action potential on B neurons. (2) F suc blocked the synaptic transmission of some B neurons within 0.5￣3 min. The rapid effect was concentration dependent. (3) These results suggested that F suc Reduced rapid effects of synaptic transmission of B neurons in BFSG. The rapid effect might be elicited by non genomic mechanism .It was more likely that F suc exerted its rapid effects by binding to the specific surface membrane receptors of steroid hormones on the B neurons. It was also correlated with modulating N receptor in the postsynaptic membrane. The results also suggested that during stress, native glucocorticoid, F suc, might modulate the function of sympathetic nervous system rapidly and take part in its local negative feedback regulation in BFSG.