RT Journal Article
SR Electronic
T1 Synchronized oscillations in hippocampal CA3 neurons induced by metabotropic glutamate receptor activation
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 8039
OP 8052
DO 10.1523/JNEUROSCI.15-12-08039.1995
VO 15
IS 12
A1 GW Taylor
A1 LR Merlin
A1 RK Wong
YR 1995
UL http://www.jneurosci.org/content/15/12/8039.abstract
AB The metabotropic glutamate receptor agonist (1S,3R)-1-aminocyclopentane- 1,3 dicarboxylic acid (ACPD) at concentrations above 60 microM produced stereotypic oscillatory activity in CA3 pyramidal cells of rat hippocampal slices. This oscillatory activity consisted of trains of depolarizations with overriding action potentials. On average, individual trains lasted 7 sec and recurred at intervals of 24 sec. During each train, the constituent depolarizations achieved a maximum frequency of 27 Hz, then slowed to 8 Hz toward the end of the train. Extracellular and dual intracellular recordings suggested that this ACPD-induced oscillatory activity occurred synchronously in the CA3 population. The oscillations persisted in the presence of GABAA, GABAB, and NMDA receptor antagonists. In contrast, the oscillations were blocked by the AMPA/kainate receptor antagonist 6-cyano-7- nitroquinoxaline-2,3-dione (CNQX; 10–30 microM). Likewise, the oscillations were blocked by the metabotropic glutamate receptor antagonists (+)-alpha-methyl-4-carboxyphenylglycine [(+)-MCPG; 1 mM], (S)-4-carboxy-3-hydroxyphenylglycine [(S)-4C3HPG; 1mM] and (S)-4- carboxyphenylglycine [(S)-4CPG; 1 mM]. The results suggest that activation of metabotropic glutamate receptors can result in a permissive state that allows AMPA/kainate receptor-mediated conductances to mediate synchronized activity among hippocampal CA3 neurons.