Behavioral response to emotional stress in rabbits: role of serotonin and serotonin2A receptors.
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.
Aloyo
Vincent J
VJ
Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102, USA. Vincent.Aloyo@drexelmed.edu
Dave
Kuldip D
KD
D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology; D002065:Buspirone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005464:Fluorobenzenes / Q000494:pharmacology; D019416:Head Movements / Q000187:drug effects; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D010880:Piperidines / Q000494:pharmacology; D011817:Rabbits; D012701:Serotonin / Q000494:pharmacology / Q000502:physiology*; D058826:Serotonin 5-HT2 Receptor Agonists; D058830:Serotonin 5-HT2 Receptor Antagonists; D013315:Stress, Psychological / Q000378:metabolism / Q000517:prevention & control* / Q000601:surgery
D005464:Fluorobenzenes; D010880:Piperidines; D058826:Serotonin 5-HT2 Receptor Agonists; D058830:Serotonin 5-HT2 Receptor Antagonists; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; C079049:volinanserin; D002065:Buspirone