title: Evidence supporting a role for corticotropin-releasing factor type 2 (CRF2) receptors in the regulation of subpopulations of serotonergic neurons.
abstract: Corticotropin-releasing factor (CRF)-related peptides can modulate stress-related physiology and behavior. Some of these effects may be mediated via the CRF type 2 (CRF2) receptor on serotonergic neurons in the dorsal raphe nucleus (DR). To determine if the CRF2 receptor agonist urocortin 2 (Ucn 2) increases c-Fos expression in rat DR serotonergic neurons via actions on CRF2 receptors, we gave intracerebroventricular (icv) injections of mouse Ucn 2 after icv injections of either saline or the CRF2 receptor antagonist antisauvagine-30 (ASV-30). Double immunostaining methods for c-Fos and tryptophan hydroxylase revealed that, consistent with previous studies, mouse Ucn 2 increased c-Fos expression in tryptophan hydroxylase immunostained neurons in the middle and caudal parts (-8.18, -8.54, and -9.16 mm bregma) of the dorsal subdivision of the dorsal raphe nucleus 2 h after drug treatment. Pre-treatment with ASV-30 blocked these effects. Mouse Ucn 2 had no effect on c-Fos expression within the median raphe nucleus, consistent with the hypothesis that Ucn 2 has specific actions on an anatomically and functionally distinct subset of serotonergic neurons via activation of CRF2 receptors. These findings are also consistent with the hypothesis that Ucn 2, or another CRF-related neuropeptide acting at CRF2 receptors, modulates physiological and behavioral responses to stress-related stimuli via actions on a specific subset of serotonergic neurons within the dorsal raphe nucleus.
authors.affiliation: Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, UK. d.staub@bristol.ac.uk
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Staub
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Evans
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Lowry
mesh_terms: D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology; D007150:Immunohistochemistry / Q000379:methods; D007276:Injections, Intraventricular; D008297:Male; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D011903:Raphe Nuclei / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D018019:Receptors, Corticotropin-Releasing Hormone / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*; D012701:Serotonin / Q000378:metabolism*; D013194:Staining and Labeling; D014365:Tryptophan Hydroxylase / Q000378:metabolism; D054832:Urocortins
chemical_list: C101531:CRF receptor type 2; D010446:Peptide Fragments; D016760:Proto-Oncogene Proteins c-fos; D018019:Receptors, Corticotropin-Releasing Hormone; D054832:Urocortins; C116607:antisauvagine 30; C518358:urocortin 2, mouse; D012701:Serotonin; D003346:Corticotropin-Releasing Hormone; D014365:Tryptophan Hydroxylase