Corticotropin releasing hormone type 2 receptors in the dorsal raphe nucleus mediate the behavioral consequences of uncontrollable stress.
Uncontrollable shock produces a constellation of behavioral changes that are not observed after equivalent escapable shock. These include interference with escape and potentiation of fear conditioning. The activation of corticotropin-releasing hormone (CRH) receptors within the caudal dorsal raphe nucleus (DRN) during inescapable tailshock (IS) has been shown to be critical for the development of these behavioral changes. CRH binds to two receptor subtypes, both of which are found in the DRN. The present set of studies examined which CRH receptor subtype mediates the effects of IS. Intra-DRN administration of the CRH(2) receptor antagonist anti-sauvagine-30 before IS dose-dependently blocked IS-induced behavioral changes; the CRH(1) receptor antagonist 2-methyl-4-(N-propyl-N-cycloproanemethylamino)-5-chloro-6-(2,4,6-trichloranilino)pyrimidine (NBI27914), administered in the same manner, did not. Moreover, the highly selective CRH(2) receptor agonist urocortin II (Ucn II) dose-dependently caused behavioral changes associated with IS in the absence of shock. Ucn II was effective at doses 100-fold lower than those previously required for CRH. The relationship between CRH(2) receptors and DRN 5-HT is discussed.
Hammack
Sayamwong E
SE
Department of Psychiatry and Center for Behavioral Neuroscience, Emory University, Atlanta, Georgia 30322, USA. jom@psych.colorado.edu
Schmid
Megan J
MJ
LoPresti
Matthew L
ML
Der-Avakian
Andre
A
Pellymounter
Mary Ann
MA
Foster
Alan C
AC
Watkins
Linda R
LR
Maier
Steven F
SF
D000679:Amygdala / Q000187:drug effects / Q000502:physiology; D000814:Aniline Compounds / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004597:Electroshock; D004924:Escape Reaction / Q000187:drug effects / Q000502:physiology; D005239:Fear / Q000502:physiology; D006380:Helplessness, Learned; D008297:Male; D008845:Microinjections; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D010446:Peptide Fragments / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D011903:Raphe Nuclei / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018019:Receptors, Corticotropin-Releasing Hormone / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism; D013312:Stress, Physiological / Q000503:physiopathology*; D054832:Urocortins
C471210:2-methyl-4-(N-propyl-N-cycloproanemethylamino)-5-chloro-6-(2,4,6-trichloranilino)pyrimidine; D000814:Aniline Compounds; D010446:Peptide Fragments; D011743:Pyrimidines; D018019:Receptors, Corticotropin-Releasing Hormone; D054832:Urocortins; C116607:antisauvagine 30; D012701:Serotonin; D003346:Corticotropin-Releasing Hormone