title: The Effects of Prior Stress on Anxiety-Like Responding to Intra-BNST Pituitary Adenylate Cyclase Activating Polypeptide in Male and Female Rats.
abstract: Chronic or repeated exposure to stressful stimuli can result in several maladaptive consequences, including increased anxiety-like behaviors and altered peptide expression in anxiety-related brain structures. Among these structures, the bed nucleus of the stria terminalis (BNST) has been implicated in emotional behaviors as well as regulation of hypothalamic-pituitary-adrenal (HPA) axis activity. In male rodents, chronic variate stress (CVS) has been shown to increase BNST pituitary adenylate cyclase activating polypeptide (PACAP) and its cognate PAC1 receptor transcript, and BNST PACAP signaling may mediate the maladaptive changes associated with chronic stress. Here, we examined whether CVS would sensitize the behavioral and/or endocrine response to a subthreshold BNST PACAP infusion. Male and cycling female rats were exposed to a 7 day CVS paradigm previously shown to upregulate BNST PAC1 receptor transcripts; control rats were not stressed. Twenty-four hours following the last stressor, rats were bilaterally infused into the BNST with a normally subthreshold dose of PACAP. We found an increase in startle amplitude and plasma corticosterone levels 30 min following intra-BNST PACAP infusion in male rats that had been previously exposed to CVS. CVS did not enhance the startle response in cycling females. Equimolar infusion of the VPAC1/2 receptor ligand vasoactive intestinal polypeptide (VIP) had no effect on plasma corticosterone levels even in previously stressed male rats. These results suggest that repeated exposure to stressors may differentially alter the neural circuits underlying the responses to intra-BNST PACAP, and may result in different anxiety-like responses in males and females.
authors.affiliation: Department of Psychological Science, University of Vermont, Burlington, VT, USA.
authors.forename: S Bradley
authors.initials: SB
authors.lastname: King
authors.affiliation: Department of Psychiatry, Harvard University and McLean Hospital, Belmont, MA, USA.
authors.forename: Kim R
authors.initials: KR
authors.lastname: Lezak
authors.affiliation: Department of Psychological Science, University of Vermont, Burlington, VT, USA.
authors.forename: Micaela
authors.initials: M
authors.lastname: O'Reilly
authors.affiliation: Department of Psychological Science, University of Vermont, Burlington, VT, USA.
authors.forename: Donna J
authors.initials: DJ
authors.lastname: Toufexis
authors.affiliation: Department of Psychological Science, University of Vermont, Burlington, VT, USA.
authors.forename: William A
authors.initials: WA
authors.lastname: Falls
authors.affiliation: Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, VT, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Braas
authors.affiliation: Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, VT, USA.
authors.forename: Victor
authors.initials: V
authors.lastname: May
authors.affiliation: Department of Psychological Science, University of Vermont, Burlington, VT, USA.
authors.forename: Sayamwong E
authors.initials: SE
authors.lastname: Hammack
mesh_terms: D000818:Animals; D001007:Anxiety / Q000503:physiopathology*; D003345:Corticosterone / Q000097:blood; D005260:Female; D008297:Male; D008845:Microinjections; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000008:administration & dosage / Q000494:pharmacology / Q000502:physiology*; D051381:Rats; D013216:Reflex, Startle / Q000187:drug effects; D012686:Septal Nuclei / Q000187:drug effects / Q000502:physiology*; D012727:Sex Characteristics; D013315:Stress, Psychological / Q000503:physiopathology*; D014660:Vasoactive Intestinal Peptide / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D014660:Vasoactive Intestinal Peptide; D003345:Corticosterone