title: Interplay between non-NMDA and NMDA receptor activation during oscillatory wave propagation: Analyses of caffeine-induced oscillations in the visual cortex of rats.
abstract: Generation and propagation of oscillatory activities in cortical networks are important features of the brain. However, many issues related to oscillatory phenomena are unclear. We previously reported neocortical oscillation following caffeine treatment of rat brain slices. Input to the primary visual cortex (Oc1) generates N-methyl-d-aspartate (NMDA) receptor-dependent oscillations, and we proposed that the oscillatory signals originate in the secondary visual cortex (Oc2). Because non-NMDA and NMDA receptors cooperate in synaptic transmission, non-NMDA receptors may also play an important role in oscillatory activities. Here we investigated how non-NMDA receptor activities contribute to NMDA receptor-dependent oscillations by using optical recording methods. After induction of stable oscillations with caffeine application, blockade of NMDA receptors abolished the late stable oscillatory phase, but elicited 'hidden' non-NMDA receptor-dependent oscillation during the early depolarizing phase. An interesting finding is that the origin of the non-NMDA receptor-dependent oscillation moved from the Oc1, during the early phase, toward the origin of the NMDA receptor-dependent oscillation that is fixed in the Oc2. In addition, the frequency of the non-NMDA receptor-dependent oscillation was higher than that of the NMDA receptor-dependent oscillation. Thus, in one course of spatiotemporal oscillatory activities, the relative balance in receptor activities between non-NMDA and NMDA receptors gradually changes, and this may be due to the different kinetics of the two receptor types. These results suggest that interplay between the two receptor types in the areas of Oc1 and Oc2 may play an important role in oscillatory signal communication.
authors.affiliation: Department of Molecular Oral Physiology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto, Tokushima 770-8504, Japan; Department of Physiology, Kanazawa Medical University, Uchinada-cho, Ishikawa, 920-0293, Japan. Electronic address: hyoshimu@tokushima-u.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yoshimura
authors.affiliation: Department of Physiology, Kanazawa Medical University, Uchinada-cho, Ishikawa, 920-0293, Japan.
authors.forename: Tokio
authors.initials: T
authors.lastname: Sugai
authors.affiliation: Department of Physiology, Kanazawa Medical University, Uchinada-cho, Ishikawa, 920-0293, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kato
authors.affiliation: Laboratory for Neural Circuit Systems, Institute of Neuroscience, Tokushima Bunri University, 1314-1, Shido, Kagawa, 769-2123, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tominaga
authors.affiliation: Laboratory for Neural Circuit Systems, Institute of Neuroscience, Tokushima Bunri University, 1314-1, Shido, Kagawa, 769-2123, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Tominaga
authors.affiliation: Department of Molecular Oral Physiology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto, Tokushima 770-8504, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Hasegawa
authors.affiliation: Department of Molecular Oral Physiology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto, Tokushima 770-8504, Japan.
authors.forename: Chenjuan
authors.initials: C
authors.lastname: Yao
authors.affiliation: Department of Molecular Oral Physiology, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto, Tokushima 770-8504, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Akamatsu
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000187:drug effects* / Q000502:physiology*; D002110:Caffeine / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000819:agonists / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D014793:Visual Cortex / Q000187:drug effects* / Q000502:physiology*
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate; D002110:Caffeine
keywords: NMDA receptor; Non-NMDA receptor; Optical recording; Oscillation; Rat; Visual cortex