title: Constitutive Increases in Amygdalar Corticotropin-Releasing Factor and Fatty Acid Amide Hydrolase Drive an Anxious Phenotype.
abstract: BACKGROUND
  Corticotropin-releasing factor (CRF) mediates anxiogenic responses by activating CRF type 1 (CRF1) receptors in limbic brain regions. Anxiety is further modulated by the endogenous cannabinoid (eCB) system that attenuates the synaptic effects of stress. In the amygdala, acute stress activates the enzymatic clearance of the eCB N-arachidonoylethanolamine via fatty acid amide hydrolase (FAAH), although it is unclear whether chronic dysregulation of CRF systems induces maladaptive changes in amygdalar eCB signaling. Here, we used genetically selected Marchigian Sardinian P (msP) rats carrying an innate overexpression of CRF1receptors to study the role of constitutive upregulation in CRF systems on amygdalar eCB function and persistent anxiety-like effects.
  
  
  METHODS
  We applied behavioral, pharmacological, and biochemical methods to broadly characterize anxiety-like behaviors and amygdalar eCB clearance enzymes in msP versus nonselected Wistar rats. Subsequent studies examined the influence of dysregulated CRF and FAAH systems in altering excitatory transmission in the central amygdala (CeA).
  
  
  RESULTS
  msPs display an anxious phenotype accompanied by elevations in amygdalar FAAH activity and reduced dialysate N-arachidonoylethanolamine levels in the CeA. Elevations in CRF-CRF1signaling dysregulate FAAH activity, and this genotypic difference is normalized with pharmacological blockade of CRF1receptors. msPs also exhibit elevated baseline glutamatergic transmission in the CeA, and dysregulated CRF-FAAH facilitates stress-induced increases in glutamatergic activity. Treatment with an FAAH inhibitor relieves sensitized glutamatergic responses in msPs and attenuates the anxiety-like phenotype.
  
  
  CONCLUSIONS
  Pathological anxiety and stress hypersensitivity are driven by constitutive increases in CRF1signaling that dysregulate N-arachidonoylethanolamine signaling mechanisms and reduce neuronal inhibitory control of CeA glutamatergic synapses.
authors.affiliation: Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Natividad
authors.affiliation: Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California; Virginia Tech School of Neuroscience, Virginia Tech, Blacksburg, Virginia.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Buczynski
authors.affiliation: Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California.
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Herman
authors.affiliation: Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California.
authors.forename: Dean
authors.initials: D
authors.lastname: Kirson
authors.affiliation: Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Oleata
authors.affiliation: Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California.
authors.forename: Cristina
authors.initials: C
authors.lastname: Irimia
authors.affiliation: Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California.
authors.forename: Ilham
authors.initials: I
authors.lastname: Polis
authors.affiliation: School of Pharmacy, Pharmacology Unit, University of Camerino, Camerino, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Ciccocioppo
authors.affiliation: Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California. Electronic address: mroberto@scripps.edu.
authors.forename: Marisa
authors.initials: M
authors.lastname: Roberto
authors.affiliation: Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California.
authors.forename: Loren H
authors.initials: LH
authors.lastname: Parsons
mesh_terms: D000581:Amidohydrolases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000679:Amygdala / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001007:Anxiety / Q000188:drug therapy / Q000473:pathology*; D002186:Cannabinoids / Q000378:metabolism; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism*; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000235:genetics; D005106:Exploratory Behavior / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D018377:Neurotransmitter Agents / Q000378:metabolism; D018408:Patch-Clamp Techniques; D010880:Piperidines / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D051381:Rats; D011922:Rats, Mutant Strains; D018019:Receptors, Corticotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism; D000099052:CRF Receptor, Type 1; D000099252:Fatty Acid Amide Hydrolases
chemical_list: D000581:Amidohydrolases; D002186:Cannabinoids; D003346:Corticotropin-Releasing Hormone; D004791:Enzyme Inhibitors; D018377:Neurotransmitter Agents; D010880:Piperidines; D011725:Pyridines; D011743:Pyrimidines; D018019:Receptors, Corticotropin-Releasing Hormone; D000099052:CRF Receptor, Type 1; D000099252:Fatty Acid Amide Hydrolases; C528552:N,N-bis(2-methoxyethyl)-3-(4-methoxy-2-methylphenyl)-2,5-dimethyl-pyrazolo(1,5-a)pyrimidin-7-amine; C557973:PF 3845
keywords: Anxiety; CRF1; Central amygdala (CeA); Endocannabinoid; Excitatory; Glutamate