Author : Katherine L. Eaton
Publisher :
ISBN 13 :
Total Pages : 194 pages
Book Rating : 4.:/5 (317 download)
Book Synopsis Neuropeptide Receptors in the Amygdala by : Katherine L. Eaton
Download or read book Neuropeptide Receptors in the Amygdala written by Katherine L. Eaton and published by . This book was released on 2007 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stress is a known factor in psychiatric illness. Understanding the mechanisms by which stress precipitates these illnesses are of paramount concern. Since anxiety disorder are highly comorbid with mood disorders, understanding the common symptoms of these illnesses could indicate functional changes that elicit these symptoms. Also, alterations in the hypothalamo-pituitary-adrenal (HPA) axis, the system involved in maintaining homeostasis, are observed in many mood and anxiety disorders. The amygdala has been shown to modulate anxiety behavior and HPA axis function. The amygdala receives inputs from many sensory cortices and has projections reaching the hypothalamus and mid- and hindbrain regions. These connections allow integration of sensory signal and can produce the necessary signaling to induce responses to maintain homeostasis following stress. This signaling occurs through various neurotransmitters. The longest lasting and farthest reaching of these are neuropeptides. Two neuropeptides, corticotropin-releasing hormone (CRH) and neuropeptide Y (NPY), have been shown to alter anxiety behavior and HPA axis function. These changes are mediated through multiple receptors. This dissertation endeavors to understand how certain CRH and NPY receptors are regulated by glucocorticoid and chronic stress. The receptors to be investigated in this thesis include the CRH type 2 receptor (CRH-R2), NPY type 1 receptor (NPY-Y1) and the glucocorticoid induced receptor (GIR). In vitro analysis was used to investigate changes in the expression of CRH-R2, NPY-Y1 and GIR following glucocorticoid exposure. CRH-R2 and GIR could be down regulated by glucocorticoids and NPY-Y1 was up regulated. Possible mechanisms for these dexamethasone-mediated changes are discussed. In vivo studies determined the regulation of CRH-R2, NPY-Y1 and GIR expression by chronic stress in the central and medial amygdala, both known to mediate anxiety behavior and HPA axis function. The Chronic Variable Stress (CVS) paradigm used is known to elicit changes similar to those observed in depression, such as altered HPA axis function, increased anxiety and anhedonia. Alteration in neuropeptide receptor expression could contribute to these changes. In the central amygdala, CRH-R2 is down regulated following 14 days of CVS, while NPY-Y1 and GIR had no effect. In the medial amygdala, GIR is up regulated while CRH-R2 and NPY-Y1 are unchanged.