Behavioral response to emotional stress in rabbits: role of serotonin and serotonin2A receptors

Behav Pharmacol. 2007 Nov;18(7):651-9. doi: 10.1097/FBP.0b013e3282effc0d.

Abstract

Exposure to a novel environment is a stressor which modulates behavior, increases stress hormones and enhances the release of several neurotransmitters including serotonin (5-HT). Exposing rabbits to a novel environment significantly increases head-bob behavior but fails to alter either grooming or wet dog shakes compared with those observed in the home-cage. The goal of this study was to determine the role of 5-HT and its receptors in mediating novelty-elicited head-bob behavior. Reduction of central 5-HT levels after treatment with the serotonergic neurotoxin 5,7-DHT significantly decreased novelty-elicited head bobs by 40% compared with those in sham-lesioned rabbits, indicating that 5-HT mediates, in part, this behavior. Additionally, pretreatment with the 5-HT1A partial agonist and clinically used anxiolytic buspirone also significantly attenuated novelty-elicited head bobs. Pretreatment with the selective 5-HT2A antagonist M 100,907 significantly reduced novel environment-elicited head bobs by 40%. Furthermore, agonist-induced reduction of cortical 5-HT2A receptor density resulted in a significant 40% reduction in the number of head bobs elicited by the novel environment. These data demonstrate that rabbit head-bob behavior, an index of the response to novelty stress, is mediated, in part, by 5-HT activation of 5-HT2A receptors.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 5,7-Dihydroxytryptamine / pharmacology
  • Animals
  • Behavior, Animal / drug effects*
  • Behavior, Animal / physiology
  • Buspirone / pharmacology
  • Dose-Response Relationship, Drug
  • Fluorobenzenes / pharmacology
  • Head Movements / drug effects
  • Male
  • Motor Activity / drug effects
  • Piperidines / pharmacology
  • Rabbits
  • Serotonin / pharmacology
  • Serotonin / physiology*
  • Serotonin 5-HT2 Receptor Agonists*
  • Serotonin 5-HT2 Receptor Antagonists*
  • Stress, Psychological / metabolism
  • Stress, Psychological / prevention & control*
  • Stress, Psychological / surgery

Substances

  • Fluorobenzenes
  • Piperidines
  • Serotonin 5-HT2 Receptor Agonists
  • Serotonin 5-HT2 Receptor Antagonists
  • 5,7-Dihydroxytryptamine
  • Serotonin
  • volinanserin
  • Buspirone