Effect of social status on striatal dopamine D2 receptor binding characteristics in cynomolgus monkeys assessed with positron emission tomography

✍ Scribed by Kathleen A. Grant; Carol A. Shively; Michael A. Nader; Richard L. Ehrenkaufer; Scott W. Line; Thomas E. Morton; H. Donald Gage; Robert H. Mach

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 137 KB
• Volume: 29
• Category: Article
• ISSN: 0887-4476
• DOI: 10.1002/(sici)1098-2396(199805)29:1<80::aid-syn7>3.0.co;2-7

✦ Synopsis

Stress is believed to be a major factor in the etiology and expression of a number of behavioral disorders . Although animal models have addressed various aspects of stress and related aberrant behaviors, a majority of these studies have used acute or short-term exposure to stress and physical stressors (e.g., forced swimming, electrical shock, etc.) to induce a stress response . However, the derivation and chronicity of stress are important design considerations for models of human disease. One model of chronic stress in primates is derived from linear social status hierarchies that characterize social organization in macaques . Animals that live in social groups routinely experience stress arising from conspecific threat. In particular, subordinate animals show many physiological and behavioral signs of stress. It has been argued that social status hierarchies provide a ''comprehensive and appropriate model'' for the analysis of behavioral, endocrine, and brain system changes associated with chronic social stress . In small social groups of cynomolgus monkeys (Macaca fascicularis) formed in laboratory settings, subordinate females display heightened hypothalamic-pituitaryadrenal axis activity, suppressed ovarian function, and social isolation .

Data primarily from rodent models strongly suggest that both acute and chronic stress result in increased dopaminergic levels in striatal dopaminergic pathways . The heightened dopaminergic activity during chronic stress is associated with a decreased sensitivity to dopaminergic agonists, particularly D 2 receptor agonists, and a decrease in D 2 receptor number in the nucleus accumbens (Papp et al.,