Power spectral electroencephalogram analysis of the effects of ritanserin in freely moving rats during quiet waking

S. Moyanova, R. Kirov, V. Ivanova

Research output: Contribution to journalArticlepeer-review


Changes in the spectral characteristics of the Fast Fourier Transformed (FFT) electroencephalogram (EEG) recorded from the frontal cortex of freely moving rats during quiet waking were studied after blockade of the 5-hydroxytryptamine-2 (5-HT 2) receptors by the potent and long acting 5-HT 2 antagonist ritanserin administered intraperitoneally (i.p.) at two doses (0.63 and 2.5 mg/kg). The rationale of this approach was to evaluate the subtle ritanserin-induced changes in the EEG in the frequency domain, and thus obtain more information about the neurophysiological effects mediated by brain 5-HT 2 receptors and about the mechanisms underlying ritanserin's ability to increase sleep at the expense of wakefulness. Ritanserin induced significant changes in the power spectrum of EEG recorded from the frontal cortex. The activation index (the ratio of the dominant frequency in the power spectrum to the total power) significantly decreased after ritanserin, which was due to the increased EEG power in all frequency bands (except for β 2) and to the decreased dominant frequency in the EEG spectrum, suggesting ritanserin-reduced EEG activation during quiet waking. The results favor the view of the excitatory modulating action of serotonin mediated via cortical 5-HT 2 receptors and suggest that ritanserin could cause a faster transition from waking to sleep.

Original languageEnglish
Pages (from-to)605-611
Number of pages7
JournalMethods and Findings in Experimental and Clinical Pharmacology
Issue number9
Publication statusPublished - 1997


  • 5-HT receptor antagonist
  • EEG spectral analysis
  • Rat
  • Ritanserin

ASJC Scopus subject areas

  • Pharmacology (medical)
  • Pharmacology, Toxicology and Pharmaceutics(all)


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