ASSESSMENT OF NORADRENERGIC FUNCTIONING IN PATIENTS WITH NON-COMBAT-RELATED POSTTRAUMATIC-STRESS-DISORDER - A STUDY WITH DESMETHYLIMIPRAMINE AND ORTHOSTATIC CHALLENGES

The functioning of the noradrenergic system was assessed in 16 patient s with non-combat-related posttraumatic stress disorder (PTSD) and the same number of age- and sex-matched healthy subjects by measuring (1) plasma norepinephrine (NE) levels in supine and upright postures, and (2) growth hormone (GH) responses to challenge with desmethylimiprami ne (DMI), a NE reuptake inhibitor. Subjects were cannulated at 08:30 h after an overnight fast. Blood samples were drawn for NE levels with subjects in a supine position and after 5 min of standing. After subje cts were allowed to rest for 30 min in a supine position, a blood samp le was drawn for basal GH (T--15) levels. The second baseline sample w as drawn 15 min later (T-0), at which time DMI (1 mg/kg) was given ora lly, and further blood samples were drawn at 90, 120, and 180 min. PTS D patients had significantly higher baseline NE levels and blunted NE responsivity to postural challenge compared with normal subjects. Basa l and DMI-induced GH levels, on the other hand, did not differ in PTSD versus normal subjects. Overall, these findings suggest that non-comb at-related PTSD patients have peripheral noradrenergic dysregulation, but central postsynaptic alpha(2)-adrenergic receptor sensitivity is n ot altered in this patient population.