Theta-burst stimulation induces LTP at excitatory and inhibitory synapses in the spinal trigeminal subnucleus interpolaris.
Long-lasting synaptic modifications of excitatory and inhibitory synaptic transmissions induced by theta-burst stimulation (TBS) were examined in the spinal trigeminal subnucleus interpolaris (Vi). We found that conditioning afferents of another subnucleus caudalis (Vc) to the Vi with TBS produced long-term depression (LTD). However, when GABAA and glycine receptors were blocked, the same stimulation paradigm produced long-term potentiation (LTP). The induction of LTP involved neither NMDA receptors nor a presynaptic change. The expression of LTP was obviously suppressed by the activation of group I mGluRs because its magnitude increased in the presence of antagonists for group I mGluRs. Besides the LTP at excitatory synapses, TBS also induced LTP at inhibitory GABAergic synapses, which required the activation of NMDA receptors and NO-cGMP signaling but was not involved in the increase of postsynaptic Ca(2+) concentration. Therefore, this study shows, for the first time, an activity-dependent plasticity at excitatory and inhibitory synapses in the Vi by the same conditioning stimulation.
Department of Oral Physiology, School of Dentistry, Kyungpook National University, 2177 Dalgubeol Blvd, Jung-gu, Daegu 700-706, Republic of Korea.
Ji-Hyeon
JH
Song
Department of Oral Physiology, School of Dentistry, Kyungpook National University, 2177 Dalgubeol Blvd, Jung-gu, Daegu 700-706, Republic of Korea. Electronic address: dyoun@knu.ac.kr.
Dong-Ho
DH
Youn
D000818:Animals; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials; D005260:Female; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D053444:Inhibitory Postsynaptic Potentials; D017774:Long-Term Potentiation; D008297:Male; D009569:Nitric Oxide / Q000096:biosynthesis; D017207:Rats, Sprague-Dawley; D018009:Receptors, Glycine / Q000037:antagonists & inhibitors; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission; D013826:Theta Rhythm; D014279:Trigeminal Nucleus, Spinal / Q000187:drug effects / Q000502:physiology*
D058787:GABA-A Receptor Antagonists; D018009:Receptors, Glycine; D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; D009569:Nitric Oxide
Excitatory synapse; GABAergic synapse; LTP; Nitric oxide; Spinal trigeminal nucleus