Fast cortical oscillation after thalamic degeneration: pivotal role of NMDA receptor.
We examined electrophysiological and molecular changes of the thalamocortical system after thalamic degeneration in Purkinje cell degeneration (pcd) mice. In pcd mice, neurons in specific thalamic nuclei including the ventral medial geniculate nucleus began to degenerate around postnatal day 50, whereas the visual thalamic nucleus and nonspecific thalamic nuclei remained almost intact. In association with the morphological changes, auditory evoked potentials in the primary auditory cortex (AC) began to decrease gradually. Fast Fourier transform analysis of spontaneous cortical field potentials revealed that fast oscillation (FO) around 25 Hz occurred in the AC but not in the visual cortex. Quantitative mRNA analysis demonstrated that expression of the N-methyl-D-aspartate (NMDA) receptor was up-regulated in the AC but not in the visual cortex. Systemic administration of an NMDA antagonist abolished the FO in the AC. These results indicate that increased NMDA activity may cause the FO in the AC of pcd mice.
Kyuhou
Shin-ichi
S
Department of Physiology, Kansai Medical University, Moriguchi, Osaka 570-8506, Japan. kyuho@takii.kmu.ac.jp
Gemba
Hisae
H
D000818:Animals; D001303:Auditory Cortex / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D005072:Evoked Potentials, Auditory / Q000187:drug effects; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005260:Female; D005583:Fourier Analysis; D015870:Gene Expression; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011689:Purkinje Cells / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D013786:Thalamic Diseases / Q000235:genetics / Q000503:physiopathology*; D013788:Thalamus / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D014793:Visual Cortex / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology
D018691:Excitatory Amino Acid Antagonists; D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; D016291:Dizocilpine Maleate