title: Microinjection of urocortin 2 into the dorsal raphe nucleus activates serotonergic neurons and increases extracellular serotonin in the basolateral amygdala.
abstract: The intra dorsal raphe nucleus (DRN) administration of corticotropin releasing hormone (CRF) inhibits serotonergic (5-HT) activity in this structure, an effect blocked by antagonists selective for the type 1 CRF receptor (CRF1). The DRN has a high density of the type 2 receptor (CRF2), and so the present experiments explored the impact of CRF2 activation within the DRN on 5-HT function. The intra-DRN administration of the selective CRF2 agonist urocortin 2 (Ucn 2) dose dependently increased 5-HT efflux in the basolateral amygdala, a projection region of the DRN. Intra-DRN Ucn 2 also increased c-fos expression in labeled 5-HT neurons. Both of these effects of Ucn 2 were completely blocked by intra-DRN antisauvagine-30 (ASV-30), a relatively selective CRF2 antagonist. These data suggest that CRF1 and CRF2 activation within the DRN affect 5-HT neurons in opponent fashion. Implications of these results for understanding the behavioral effects of CRF and other CRF-like ligands are discussed.
authors.affiliation: Department of Psychology and Center for Neuroscience, University of Colorado at Boulder, Boulder, CO 80309-0345, USA. amat@psych.colorado.edu
authors.forename: J
authors.initials: J
authors.lastname: Amat
authors.forename: J P
authors.initials: JP
authors.lastname: Tamblyn
authors.forename: E D
authors.initials: ED
authors.lastname: Paul
authors.forename: S T
authors.initials: ST
authors.lastname: Bland
authors.forename: P
authors.initials: P
authors.lastname: Amat
authors.forename: A C
authors.initials: AC
authors.lastname: Foster
authors.forename: L R
authors.initials: LR
authors.lastname: Watkins
authors.forename: S F
authors.initials: SF
authors.lastname: Maier
mesh_terms: D000679:Amygdala / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002452:Cell Count / Q000379:methods; D003346:Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D003952:Diagnostic Imaging / Q000379:methods; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005110:Extracellular Space / Q000187:drug effects; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D017551:Microdialysis / Q000379:methods; D008845:Microinjections / Q000379:methods; D010446:Peptide Fragments / Q000494:pharmacology; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D011903:Raphe Nuclei / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D012701:Serotonin / Q000378:metabolism*; D013997:Time Factors; D054832:Urocortins
chemical_list: D010446:Peptide Fragments; D016760:Proto-Oncogene Proteins c-fos; D054832:Urocortins; C116607:antisauvagine 30; D012701:Serotonin; D003346:Corticotropin-Releasing Hormone