Serotoninergic modulation of GABAergic synaptic transmission in developing rat CA3 pyramidal neurons

In Sun Choi, Jin Hwa Cho, Jung Tak Kim, Eun Joo Park, Maan Gee Lee, Hong In Shin, Byung Ju Choi, Il Sung Jang

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Serotoninergic modulation of GABAergic mIPSCs was investigated in immature (postnatal 12-16-days old) rat CA3 pyramidal neurons using a conventional whole-cell patch clamp technique. Serotonin or 5-hydroxytryptamine (5-HT) (10 μmol/L) transiently and explosively increased mIPSC frequency with a small increase in the current amplitude. However, 5-HT did not affect the GABA-induced postsynaptic currents, indicating that 5-HT acts presynaptically to facilitate the probability of spontaneous GABA release. The 5-HT action on GABAergic mIPSC frequency was completely blocked by 100 nmol/L MDL72222, a selective 5-HT 3 receptor antagonist, and mimicked by mCPBG, a selective 5-HT 3 receptor agonist. The 5-HT action on GABAergic mIPSC frequency was completely occluded either in the presence of 200 μmol/L Cd2+ or in the Na+-free external solution, suggesting that the 5-HT 3 receptor-mediated facilitation of mIPSC frequency requires a Ca2+influx passing through voltage-dependent Ca2+channels from the extracellular space, and that presynaptic 5-HT3 receptors are less permeable to Ca2+. The 5-HT action on mIPSC frequency in the absence or presence of extracellular Na+ gradually increased with postnatal development. Such a developmental change in the 5-HT3 receptor-mediated facilitation of GABAergic transmission would play important roles in the regulation of excitability as well as development in CA3 pyramidal neurons.

Original languageEnglish
Pages (from-to)2342-2353
Number of pages12
JournalJournal of Neurochemistry
Volume103
Issue number6
DOIs
StatePublished - Dec 2007

Keywords

  • 5-HT receptors
  • CA3 pyramidal neurons
  • GABAergic mIPSCs
  • Hippocampus
  • Ion permeability
  • Postnatal development

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