Short-term potentiation of miniature excitatory synaptic currents causes excitation of supraoptic neurons

被引:59
作者
Kombian, SB
Hirasawa, M
Mouginot, D
Chen, XH
Pittman, QJ
机构
[1] Univ Calgary, Fac Med, Neurosci Res Grp, Calgary, AB T2N 4N1, Canada
[2] Univ Calgary, Fac Med, Dept Physiol & Biophys, Calgary, AB T2N 4N1, Canada
[3] Kuwait Univ, Fac Pharm, Safat 13110, Kuwait
[4] Univ Laval, CHUL, Res Ctr, Quebec City, PQ G1V 4G2, Canada
关键词
D O I
10.1152/jn.2000.83.5.2542
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
Magnocellular neurons (MCNs) of the hypothalamic supraoptic nucleus (SON) secrete vasopressin and oxytocin. With the use of whole-cell and nystatin-perforated patch recordings of MCNs in current- and voltage-clamp modes, we show that high-frequency stimulation (HFS, 10-200 Hz) of excitatory afferents induces increases in the frequency and amplitude of 2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo(f)quinoxaline-7-sulfonamide (NBQX)-sensitive miniature excitatory postsynaptic currents (mEPSCs) lasting up to 20 min. This synaptic enhancement, referred to as short-term potentiation (STP), could be induced repeatedly; required tetrodotoxin (TTX)-dependent action potentials to initiate, but not to maintain; and was independent of postsynaptic membrane potential, N-methyl-D-aspartate (NMDA) receptors. or retrograde neurohypophyseal neuropeptide release. STP was nor accompanied by changes in the conductance of the MCNs or in the responsiveness of the postsynaptic non-NMDA receptors, as revealed by brief application of alpha-amino3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate. mEPSCs showed similar rise times before and after HFS and analysis of amplitude distributions of mEPSCs revealed one or more peaks pre-HFS and the appearance of additional peaks post-HFS. which were equidistant from the first peak. STP of mEPSCs was not associated with enhanced evoked responses, but was associated with an NBQX-sensitive increase in spontaneous activity of MCNs. Thus we have identified a particularly long-lasting potentiation of excitatory synapses in the SON, which has a presynaptic locus, is dissociated from changes in evoked release, and which regulates postsynaptic cell excitability.
引用
收藏
页码:2542 / 2553
页数:12
相关论文
共 59 条
[1]   Metaplasticity: The plasticity of synaptic plasticity [J].
Abraham, WC ;
Bear, MF .
TRENDS IN NEUROSCIENCES, 1996, 19 (04) :126-130
[2]   ACTIVITY-DEPENDENT LONG-TERM ENHANCEMENT OF TRANSMITTER RELEASE BY PRESYNAPTIC 3',5'-CYCLIC GMP IN CULTURED HIPPOCAMPAL-NEURONS [J].
ARANCIO, O ;
KANDEL, ER ;
HAWKINS, RD .
NATURE, 1995, 376 (6535) :74-80
[4]  
Atluri PP, 1998, J NEUROSCI, V18, P8214
[5]  
Auger C, 1998, J NEUROSCI, V18, P4532
[6]  
Bao JP, 1998, J NEUROSCI, V18, P8740
[7]   Cable properties of cultured hippocampal neurons determined from sucrose-evoked miniature EPSCs [J].
Bekkers, JM ;
Stevens, CF .
JOURNAL OF NEUROPHYSIOLOGY, 1996, 75 (03) :1250-1255
[8]   PRESYNAPTIC MECHANISM FOR LONG-TERM POTENTIATION IN THE HIPPOCAMPUS [J].
BEKKERS, JM ;
STEVENS, CF .
NATURE, 1990, 346 (6286) :724-729
[9]   A SYNAPTIC MODEL OF MEMORY - LONG-TERM POTENTIATION IN THE HIPPOCAMPUS [J].
BLISS, TVP ;
COLLINGRIDGE, GL .
NATURE, 1993, 361 (6407) :31-39
[10]   Physiological evidence for local excitatory synaptic circuits in the rat hypothalamus [J].
Boudaba, C ;
Schrader, LA ;
Tasker, JG .
JOURNAL OF NEUROPHYSIOLOGY, 1997, 77 (06) :3396-3400