Effects of ritanserin on aversive classical conditioning in humans

R Hensman, Francisco S. Guimarães, M Wang, J F Deakin

Research output: Contribution to journalArticlepeer-review


According to one formulation of the behavioural functions of 5HT, aversive conditioned stimuli mediate their behavioural and emotional effects through activation of 5HT projections from dorsal raphe nucleus to receptors of the 5HT2 family in amygdala and elsewhere. To test this theory in humans, groups of ten normal volunteers received placebo, the 5HT2 lc antagonist ritanserin (10 mg PO) and no pill. Ritanserin had no effect on skin conductance level, variability (spontaneous fluctuations) or habituation to a sequence of ten neutral tones. After a conditioning trial in which tone 11 was followed by an aversive white noise, skin conductance responses to a further ten tones were enhanced. This effect was abolished by ritanserin. The results indicate a selective involvement of 5HT2/lc receptors in modulating aversively conditioned skin conductance responses.

Original languageEnglish
Pages (from-to)220-224
Number of pages5
Issue number2
Publication statusPublished - 1991


  • Adult
  • Conditioning, Classical
  • Female
  • Galvanic Skin Response
  • Humans
  • Male
  • Personality Tests
  • Piperidines
  • Receptors, Serotonin
  • Ritanserin
  • Serotonin Antagonists
  • Clinical Trial
  • Controlled Clinical Trial
  • Journal Article
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't


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