5-HT inhibits synaptic transmission in rat subthalamic nucleus neurons in vitro

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Abstract

The subthalamic nucleus (STN) plays a pivotal role in normal and abnormal motor function. We used patch pipettes to study effects of 5-HT on synaptic currents evoked in STN neurons by focal electrical stimulation of rat brain slices. 5-HT (10 μM) reduced glutamate-mediated excitatory postsynaptic currents (EPSCs) by 35±4%. However, a much higher concentration of 5-HT (100 μM) was required to inhibit GABA-mediated inhibitory postsynaptic currents (IPSCs) to a comparable extent. Concentration-response curves showed that the 5-HT inhibitory concentration 50% (IC50) for inhibition of IPSCs (20.2 μM) was more than fivefold greater than the IC50 for inhibition of EPSCs (3.4 μM). The 5-HT-induced reductions in EPSCs and IPSCs were accompanied by increases in paired-pulse ratios, indicating that 5-HT acts presynaptically to inhibit synaptic transmission. The 5-HT1B receptor antagonist NAS-181 significantly antagonized 5-HT-induced inhibitions of EPSCs and IPSCs. These studies show that 5-HT inhibits synaptic transmission in the STN by activating presynaptic 5-HT1B receptors.

Original languageEnglish (US)
Pages (from-to)1029-1033
Number of pages5
JournalNeuroscience
Volume151
Issue number4
DOIs
StatePublished - Feb 19 2008

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Keywords

  • 5-HT
  • EPSC
  • IPSC
  • brain slice
  • patch clamp
  • presynaptic inhibition

ASJC Scopus subject areas

  • Neuroscience(all)

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