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Published byEdgar Dawson Modified over 8 years ago
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A NXIOGENIC AND AVERSIVE EFFECTS OF CRF IN THE BNST IN THE RAT : ROLE OF CRF RECEPTOR SUBTYPES M.F. Olive et al
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BNST Mediates behavioral and autonomic responses to stressors Stimulation > behavioral/endocrine changes similar to those brought on by stress Inhibition > decreased response to conditioned and/or unconditioned stimulus Also see increase in learned despair with lesions and uncontrollable stress Coping mechanism?
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Hypothalamus - PVN Pituitary Adrenal Systemic Circulation amygdala BNST CRF ACTH Glucocorticoids
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CRF = neurotransmitter CRF 1 = receptor CRF 2 = receptor May (and often do) have different functions
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A IMS IntraBNST administration of CRF > stress response There are CRF 1 and CRF 2 receptors in the BNST What is the roll of each of these receptors? Let’s see what happens when we shut one of them down with an antagonist
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SPECIFICS Long-Evans (250-300g) handled Stress study while they should be asleep! BNST Cannulated Bilateral FITC labeled CRF to check placement 390 to 4700mw habituation CRF 1 antagonist CP154526 CRF 2 antagonist Antisauvagine-30 (AS-30)
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T IME L INE Cannulation EPM testing 5 days ≥ 1 week CPP testing
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E LEVATED P LUS M AZE (EPM)
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Cannulation EPM testing 5 days 1 hour habituated injection Elevated plus maze 5 min 10 min EPM
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C ONDITIONED P LACE P REFERENCE (CPP)
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CPP EPM testing ≥ 1 week Pairing of drug w/chamber days1-6 Testing Day 8 CPP testing
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EPM CP154,526 = CRF 1 antagonist AS30 = CRF 2 antagonist CRF with and without antagonist
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EPM CP154,526 = CRF 1 antagonist AS30 = CRF 2 antagonist Antagonist alone
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CP154,526 = CRF 1 antagonist AS30 = CRF 2 antagonist CPP
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D ISCUSSION Intra-BNST administration of CRF axiogenic effects Under basal levels of CRF neither antagonist effects anxiety No caged controls
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Affects performance on EPM Affects performance in CPP
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Affects Unconditioned anxiety Affects Conditioned Aversive Learning
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E LEVATED P LUS M AZE VS. C ONDITIONED P LACE P REFERENCE CRF 1 is responsible for the anxiogenic effects of CRF CRF has a higher affinity for CRF 1 More CRF 1 then CRF 2 in BNST Other studies show that CRF 2 does mediate stress to a degree These studies are nonspecific (icv, genetic knockout) o Not remembering vs not acting on bad memories o CRF 1 + 2 both increase hippocampal LTP
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T HAT MEDICAL STUFF Chronic stress elevates CRF levels in the BNST Excititory inputs from: Amygdala Ventral subiculum Limbic cortices Was 1 nano mole a physiological dose simulating a stressor? Hallmarks of PTSD Anxiety Avoidance of people, objects or places associated
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