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Social dominance in monkeys: dopamine D2 receptors and cocaine self-administration
Nature Neuroscience, Published online: 22 January 2002
February 2002 Volume 5 Number 2 pp 169 - 174

Drake Morgan(1), Kathleen A. Grant(1), H. Donald Gage(2), Robert H. Mach(1, 2), Jay R. Kaplan(3), Osric Prioleau(1), Susan H. Nader(1), Nancy Buchheimer(2), Richard L. Ehrenkaufer(2) & Michael A. Nader(1, 2)

1. Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157, USA
2. Department of Radiology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157, USA
3. Departments of Pathology (Comparative Medicine) and Anthropology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157, USACorrespondence should be addressed to M A Nader. e-mail: mnader@wfubmc.edu


Disruption of the dopaminergic system has been implicated in the etiology of many pathological conditions, including drug addiction. Here we used positron emission tomography (PET) imaging to study brain dopaminergic function in individually housed and in socially housed cynomolgus macaques (n = 20). Whereas the monkeys did not differ during individual housing, social housing increased the amount or availability of dopamine D2 receptors in dominant monkeys and produced no change in subordinate monkeys. These neurobiological changes had an important behavioral influence as demonstrated by the finding that cocaine functioned as a reinforcer in subordinate but not dominant monkeys. These data demonstrate that alterations in an organism's environment can produce profound biological changes that have important behavioral associations, including vulnerability to cocaine addiction.