Activation of serotonin receptors modulates synaptic transmission in rat cerebral cortex

Academic Article


  • The cerebral cortex receives an extensive serotonergic (5- hydroxytryptamine, 5-HT) input. Immunohistochemical studies suggest that inhibitory neurons are the main target of 5-HT innervation. In vivo extracellular recordings have shown that 5-HT generally inhibited cortical pyramidal neurons, whereas in vitro studies have shown an excitatory action. To determine the cellular mechanisms underlying the diverse actions of 5-HT in the cortex, we examined its effects on cortical inhibitory interneurons and pyramidal neurons. We found that 5-HT, through activation of 5-HT(2A) receptors, induced a massive enhancement of spontaneous inhibitory postsynaptic currents (sIPSCs) in pyramidal neurons, lasting for ~6 min. In interneurons, this 5-HT-induced enhancement of sIPSCs was much weaker. Activation of 5-HT(2A) receptors also increased spontaneous excitatory postsynaptic currents (sEPSCs) in pyramidal neurons. This response desensitized less and at a slower rate. In contrast, 5-HT slightly decreased evoked IPSCs (eIPSCs) and eEPSCs. In addition, 5-HT via 5-HT3 receptors evoked a large and rapidly desensitizing inward current in a subset of interneurons and induced a transient enhancement of sIPSCs. Our results suggest that 5-HT has widespread effects on both interneurons and pyramidal neurons and that a short pulse of 5-HT is likely to induce inhibition whereas the prolonged presence of 5-HT may result in excitation.
  • Authors

    Published In

    Digital Object Identifier (doi)

    Pubmed Id

  • 24499463
  • Author List

  • Zhou FM; Hablitz JJ
  • Start Page

  • 2989
  • End Page

  • 2999
  • Volume

  • 82
  • Issue

  • 6