title: Noradrenergic and serotonergic function in posttraumatic stress disorder.
abstract: BACKGROUND
  Yohimbine hydrochloride produces marked behavioral and cardiovascular effects in combat veterans with posttraumatic stress disorder (PTSD). In the present study, yohimbine was used as a probe of noradrenergic activity, and meta-chlorophenylpiperazine (m-CPP) as a probe of serotonergic activity. To our knowledge, this is the first study to describe the behavioral and cardiovascular effects of meta-CPP in patients with PTSD, and to compare these effects with those of yohimbine.
  
  
  METHODS
  Twenty-six patients with PTSD and 14 healthy subjects each received an intravenous infusion of yohimbine hydrochloride (0.4 mg/kg), m-CPP (1.0 mg/kg), or saline solution on 3 separate test days in a randomized balanced order and in double-blind fashion. Behavioral and cardiovascular measurements were determined at multiple times.
  
  
  RESULTS
  Eleven (42%) of the patients with PTSD experienced yohimbine-induced panic attacks and had significantly greater increases compared with controls in anxiety, panic, and PTSD symptoms, but not in cardiovascular measurements. Eight patients (31%) with PTSD experienced m-CPP-induced panic attacks and had significantly greater increases compared with controls in anxiety, panic, and PTSD symptoms, and in standing diastolic blood pressure. Yohimbine-induced panic attacks tended to occur in different patients from m-CPP-induced panic attacks.
  
  
  CONCLUSIONS
  These data suggest the presence of 2 neurobiological subgroups of patients with PTSD, one with a sensitized noradrenergic system, and the other with a sensitized serotonergic system.
authors.affiliation: Clinical Neurosciences Division, Veterans Affairs Medical Center, West Haven, Conn, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Southwick
authors.forename: J H
authors.initials: JH
authors.lastname: Krystal
authors.forename: J D
authors.initials: JD
authors.lastname: Bremner
authors.forename: C A
authors.initials: CA
authors.lastname: Morgan
authors.forename: A L
authors.initials: AL
authors.lastname: Nicolaou
authors.forename: L M
authors.initials: LM
authors.lastname: Nagy
authors.forename: D R
authors.initials: DR
authors.lastname: Johnson
authors.forename: G R
authors.initials: GR
authors.lastname: Heninger
authors.forename: D S
authors.initials: DS
authors.lastname: Charney
mesh_terms: D000328:Adult; D004311:Double-Blind Method; D006801:Humans; D006973:Hypertension / Q000139:chemically induced; D008297:Male; D009638:Norepinephrine / Q000502:physiology*; D016584:Panic Disorder / Q000139:chemically induced; D010879:Piperazines / Q000494:pharmacology; D012701:Serotonin / Q000502:physiology*; D013313:Stress Disorders, Post-Traumatic / Q000503:physiopathology*; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D010879:Piperazines; D015016:Yohimbine; D012701:Serotonin; C015068:1-(3-chlorophenyl)piperazine; D009638:Norepinephrine