海马CA_1区锥体细胞内钙离子释放与突触传递的可塑性

THE RELATIONSHIP BETWEEN CALCIUM RELEASE FROM CA_1 PYRAMIDAL NEURON INDUCED BY SYNAPTIC STIMULATION AND PLASTICITY OF SYNAPTIC TRANSMISSION IN HIPPOCAMPUS

为分析海马CA1区锥体细胞内钙离子释放与突触传递长时程增强以及长时程抑制的关系,采用全细胞膜片钳和细胞内钙成像技术,观察了不同参数的突触前刺激引起大鼠海马锥体细胞内钙离子释放的状况。结果为:100Hz、50Hz、20Hz频率,分别用50、25、15、10、5脉冲的突触前刺激均可引起锥体细胞内钙的释放,10脉冲以上的刺激引起细胞内钙释放的成功率为100％,而5脉冲的刺激引起细胞内钙的释放率为57％。100 Hz 3脉冲的刺激可引起少数锥体细胞内钙释放,而5 Hz各脉冲的刺激均不能引起锥体细胞内钙的释放。结果提示,长时程抑制时细胞内钙的升高并非来自于细胞内钙库的钙释放;引起长时程增强的刺激参数与引起锥体细胞内钙释放的参数相似。本文又分析了两者的异同处。

Whole cell patch clamp recording and calcium image technique were used to analyze the relationship between calcium release from CA1 pyramidal neuron and the plasticity of synaptic transmission in hippocampus. We observed condition of calcium release from CA1 pyramidal neuron induced by synaptic stimulation. The results showed that stimulating frequency of 100, 50, and 20 Hz when 50, 25, 15, 10 and 5 pulses were used, respectively, could evoke the calcium release from internal store of the neuron. Stimulating frequency of 5 Hz could not induce the release. When a number of stimulating pulses of 10 or higher than 10 were used, the success rate of calcium release from the internal store was 100%. But when the number of stimulating pulses of 5 was used, the rate of calcium release was 57%. The results indicate that the calcium increase in pyramidal neuron in long-term depression is not released from the internal calcium store; the stimulating protocol that induced calcium release is similar to the protocol that generated long-term potentiation, we have analyzed the similarity and difference between the two phenomena.