The Journal of Neuroscience, January 23, 2008, 28(4):893-903; doi:10.1523/JNEUROSCI.0659-07.2008
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Behavioral/Systems/Cognitive
Neuropeptide Y in the Amygdala Induces Long-Term Resilience to Stress-Induced Reductions in Social Responses But Not Hypothalamic–Adrenal–Pituitary Axis Activity or Hyperthermia
Tammy J. Sajdyk,1
Philip L. Johnson,1
Randy J. Leitermann,3
Stephanie D. Fitz,1
Amy Dietrich,1
Michelle Morin,2
Donald R. Gehlert,2
Janice H. Urban,3 and
Anantha Shekhar1
1Institute of Psychiatric Research, Department of Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana 46202, 2Eli Lilly, Indianapolis, Indiana 46201, and 3Department of Physiology and Biophysics and Interdepartmental Neurosciences Program, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064
Correspondence should be addressed to Dr. Tammy J. Sajdyk, 791 Union Drive, Institute of Psychiatric Research, Indianapolis, Indiana 46202. Email: tsajdyk{at}iupui.edu
Resilience to mental and physical stress is a key determinant for the survival and functioning of mammals. Although the importance of stress resilience has been recognized, the underlying neural mediators have not yet been identified. Neuropeptide Y (NPY) is a peptide known for its anti-anxiety-like effects mediated via the amygdala. The results of our current study demonstrate, for the first time that repeated administration of NPY directly into the basolateral nucleus of the amygdala (BLA) produces selective stress-resilient behavioral responses to an acute restraint challenge as measured in the social interaction test, but has no effect on hypothalamic–adrenal–pituitary axis activity or stress-induced hyperthermia. More importantly, the resilient behaviors observed in the NPY-treated animals were present for up to 8 weeks. Antagonizing the activity of calcineurin, a protein phosphatase involved in neuronal remodeling and present in NPY receptor containing neurons within the BLA, blocked the development of long-term, but not the acute increases in social interaction responses induced by NPY administration. This suggests that the NPY-induced long-term behavioral resilience to restraint stress may occur via mechanisms involving neuronal plasticity. These studies suggest one putative physiologic mechanism underlying stress resilience and could identify novel targets for development of therapies that can augment the ability to cope with stress.
Key words: NPY; BNST; amygdala; anxiety; anxiolytic; autonomic; CRF; CRH; hypothalamus; neuropeptide; RAPHE; septum
Received Feb. 14, 2007;
revised Dec. 6, 2007;
accepted Dec. 7, 2007.
Correspondence should be addressed to Dr. Tammy J. Sajdyk, 791 Union Drive, Institute of Psychiatric Research, Indianapolis, Indiana 46202. Email: tsajdyk{at}iupui.edu