Simultaneous NMDA-dependent long-term potentiation of EPSCs and long-term depression of IPSCs in cultured rat hippocampal neurons.
A fundamental issue in understanding activity-dependent long-term plasticity of neuronal networks is the interplay between excitatory and inhibitory synaptic drives in the network. Using dual whole-cell recordings in cultured hippocampal neurons, we examined synaptic changes occurring as a result of a transient activation of NMDA receptors in the network. This enhanced transient activation led to a long-lasting increase in synchrony of spontaneous activity of neurons in the network. Simultaneous long-term potentiation of excitatory synaptic strength and a pronounced long-term depression of inhibitory synaptic currents (LTDi) were produced, which were independent of changes in postsynaptic potential and Ca2+ concentrations. Surprisingly, miniature inhibitory synaptic currents were not changed by the conditioning, whereas both frequency and amplitudes of miniature EPSCs were enhanced. LTDi was mediated by activation of a presynaptic GABAB receptor, because it was blocked by saclofen and CGP55845 [(2S)-3-{[(15)-1-(3, 4-dichlorophenyl)ethyl]amino-2-hydroxypropyl)(phenylmethyl)phosphinic acid]. The cAMP antagonist Rp-adenosine 3 ', 5 ' -cyclic monophosphothioate abolished all measured effects of NMDA-dependent conditioning, whereas a nitric oxide synthase inhibitor was ineffective. Finally, network-induced plasticity was not occluded by a previous spike-timing-induced plasticity, indicating that the two types of plasticity may not share the same mechanism. These results demonstrate that network plasticity involves opposite affects on inhibitory and excitatory neurotransmission.
Ivenshitz
Miriam
M
Department of Neurobiology, The Weizmann Institute of Science, Rehovot, 76100, Israel.
Segal
Menahem
M
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000818:Animals; D001418:Baclofen / Q000031:analogs & derivatives / Q000494:pharmacology; D002118:Calcium / Q000032:analysis; D002478:Cells, Cultured / Q000187:drug effects / Q000502:physiology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000494:pharmacology; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology*; D006624:Hippocampus / Q000166:cytology*; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D036881:Long-Term Synaptic Depression / Q000187:drug effects / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D009569:Nitric Oxide / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019335:Nitroarginine / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D010721:Phosphinic Acids / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D018080:Receptors, GABA-B / Q000187:drug effects / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology; D013997:Time Factors
D010721:Phosphinic Acids; D011412:Propanolamines; D011810:Quinoxalines; D018080:Receptors, GABA-B; D016194:Receptors, N-Methyl-D-Aspartate; D013873:Thionucleotides; C085075:CGP 55845A; D005576:Colforsin; D019335:Nitroarginine; C016957:adenosine-3',5'-cyclic phosphorothioate; D009569:Nitric Oxide; D013779:Tetrodotoxin; C056723:FG 9041; D015763:2-Amino-5-phosphonovalerate; D000242:Cyclic AMP; D019001:Nitric Oxide Synthase; D001418:Baclofen; C080629:saclofen; D002118:Calcium