INFLUENCE OF CLONIDINE ON PSYCHOPATHOLOGICAL, ENDOCRINE AND RESPIRATORY EFFECTS OF CHOLECYSTOKININ TETRAPEPTIDE IN PATIENTS WITH PANIC DISORDER

The influence of clonidine pretreatment on psychopathological, endocri ne and respiratory effects of cholecystokinin tetrapeptide (CCK-4) was characterized. Patients with panic disorder (DSM-III-R) were given 50 mu g CCK-4 IV at 1100 hours on 2 separate study days. In a randomized double-blind design they were additionally infused with 150 mu g clon idine or placebo from 1040 to 1110 hours. After CCK-4 all patients exp erienced symptom attacks. No effects of clonidine on panic psychopatho logy or blood gas parameters were observed, After CCK-4, in the clonid ine condition the pituitary release of adrenocorticotropin (ACTH) and prolactin was seemingly enhanced compared to placebo, Our results sugg est that CCK-4-induced panic attacks are not suppressible by presynapt ic alpha-2 receptor stimulation. Moreover, they point to a synergistic postsynaptic action of clonidine to CCK-4 upon pituitary hormone secr etion. The diverging sites of action might possibly explain the discre pancies of psychopathological alterations and stress hormone secretion .