Dobrunz L E, Huang E P, Stevens C F
Molecular Neurobiology Laboratory and Howard Hughes Medical Institute, Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
Proc Natl Acad Sci U S A. 1997 Dec 23;94(26):14843-7. doi: 10.1073/pnas.94.26.14843.
Hippocampal pyramidal neurons often fire in bursts of action potentials with short interspike intervals (2-10 msec). These high-frequency bursts may play a critical role in the functional behavior of hippocampal neurons, but synaptic plasticity at such short times has not been carefully studied. To study synaptic modulation at very short time intervals, we applied pairs of stimuli with interpulse intervals ranging from 7 to 50 msec to CA1 synapses isolated by the method of minimal stimulation in hippocampal slices. We have identified three components of short-term paired-pulse modulation, including (i) a form of synaptic depression manifested after a prior exocytotic event, (ii) a form of synaptic depression that does not depend on a prior exocytotic event and that we postulate is based on inactivation of presynaptic N-type Ca2+ channels, and (iii) a dependence of paired-pulse facilitation on the exocytotic history of the synapse.
海马锥体细胞通常以动作电位爆发的形式放电，其峰电位间隔很短（2 - 10毫秒）。这些高频爆发可能在海马神经元的功能行为中起关键作用，但在如此短的时间内的突触可塑性尚未得到仔细研究。为了研究极短时间间隔内的突触调制，我们采用了成对刺激，脉冲间隔范围为7至50毫秒，施加于通过海马切片最小刺激法分离出的CA1突触。我们确定了短期成对脉冲调制的三个组成部分，包括：（i）一种在先前胞吐事件后表现出的突触抑制形式；（ii）一种不依赖于先前胞吐事件的突触抑制形式，我们推测其基于突触前N型Ca2+通道的失活；以及（iii）成对脉冲易化对突触胞吐历史的依赖性。
