title: CCK-4: Psychophysiological conditioning elicits features of spontaneous panic attacks.
abstract: BACKGROUND
  Cholecystokinin-tetrapeptide (CCK-4) is an established model to generate subjective panic anxiety. CCK-4 injection also results in consistent and dose-dependent rise of stress hormones. Effects other than upon subjective panic and stress hormone activity have barely been examined. The purpose of the study was to investigate CCK-4 effects on emotional facial expression and especially on fear relevant facial muscles establishing therewith a more objective method to measure subjective panic anxiety.
  
  
  METHODS
  20 healthy male subjects were randomly and double-blindedly assigned in two groups (dose groups), each of which was investigated three times once with placebo and twice with 25 μg or 50 μg CCK-4 respectively. Subjects of each group were randomly assigned in two different balanced orders of investigations: CCK-CCK-Placebo vs. Placebo-CCK-CCK. Facial muscle and hypothalamo-pituitary-adrenocortical (HPA)-axis activity were recorded.
  
  
  RESULTS
  CCK-4 led dose-dependently to an increase of panic anxiety, an activation of fear relevant facial muscles and a rise of stress hormones. Whereas placebo administration before CCK-4 revealed no significant panic and stress response, during placebo following CCK-4 stimulations a psychophysiological conditioning effect could be observed without rise in HPA-axis activity.
  
  
  CONCLUSIONS
  Our findings indicate the possibility to measure different intensities of panic anxiety and conditioning effects with a facial EMG method. Dissociation of HPA-activity and fear relevant facial muscle activity is in accordance with former results about spontaneous panic attacks.
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Hamburg, Martinistr 52, 20246 Hamburg, Germany. hinkelma@uke.uni-hamburg.de
authors.forename: Kim
authors.initials: K
authors.lastname: Hinkelmann
authors.forename: Alexander
authors.initials: A
authors.lastname: Yassouridis
authors.forename: Reinhard
authors.initials: R
authors.lastname: Mass
authors.forename: Henrike
authors.initials: H
authors.lastname: Tenge
authors.forename: Michael
authors.initials: M
authors.lastname: Kellner
authors.forename: Holger
authors.initials: H
authors.lastname: Jahn
authors.forename: Klaus
authors.initials: K
authors.lastname: Wiedemann
authors.forename: Karsten
authors.initials: K
authors.lastname: Wolf
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D019540:Area Under Curve; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004576:Electromyography / Q000379:methods; D005152:Facial Muscles / Q000187:drug effects / Q000503:physiopathology; D006801:Humans; D008297:Male; D010147:Pain Measurement; D016584:Panic Disorder / Q000097:blood / Q000139:chemically induced* / Q000503:physiopathology*; D011863:Radioimmunoassay / Q000379:methods; D013758:Tetragastrin / Q000009:adverse effects* / Q000097:blood; D013997:Time Factors; D055815:Young Adult
chemical_list: D013758:Tetragastrin; D000324:Adrenocorticotropic Hormone