Thomas R. Minor, Traci N. Plumb, Christopher J. Schell, Anh K. Pham
University of California, Los Angeles, California, USA
Neurobiology of Post-traumatic Stress Disorder. Hauppauge, New York: Nova Science Publishers, 2010, 376 pages.

This chapter reviews human and animal literature on the psychological and biological consequences of maintaining and intense, prolonged fear response. This type of psychological trauma alters neural regulatory mechanisms in the CNS that renders fear- and anxiety-related circuitry hyper-responsive such that individual overreact to relatively mild stressors. The metabolic challenge associated with maintaining a state of hyperactivity engages a compensatory signaling mechanism involving adenosine. We review evidence from the learned helplessness rat model of PTSD and comorbid depression that enhanced brain adenosine signaling mediates the transition from a state of anxiety and agitation to a depression-like state termed conservation-withdrawal. We also present new evidence that the conservation-withdrawal aspects of helplessness are mediated in the striatum where adenosine activates specific A2A receptors to uncouple dopamine’s motivational signal from ongoing behavior.