Distinct panicogenic activity of sodium lactate and cholecystokinin tetrapeptide in patients with panic disorder

Abstract

Rationale : The validity of experimentally induced panic attacks as a model to study the pathophysiology of panic disorder has been questioned. Unspecific, unpleasant and aversive effects as well as specific patterns of psycho vegetative symptoms pointing to different subtypes of panic disorder have been observed. These findings raise the question of challenge paradigms as a valuable tool to identify different vulnerabilities in patients with panic disorder. Methods : We compared the two most widely studied panicogenic drugs sodium lactate and cholecystokinin tetrapeptide (CCK-4) with placebo in 25 patients with panic disorder and age- and gender-matched healthy control subjects. To measure psychophysiological changes, we repeatedly administered the Acute Panic Inventory (API) and visual analogue scales for anxiety and arousal. Cardiovascular (heart rate and blood pressure) and neuroendocrine (ACTH, Cortisol and prolactin) data were recorded simultaneously. Results : In patients with panic disorder, 18 out of 26 experienced a sodium lactate- or a CCK-4 induced panic attack. Lactate or CCK-4-induced symptoms and induced panic attacks were only correlated in healthy controls, but not in patients with panic disorder. (Analysis of sodium lactate- and CCK-4-induced changes of cardiovascular and neuroendocrine parameters is in progress at the moment and results will be presented). Conclusions : The mechanisms of lactate and CCK-4 induced panic attacks are distinct in panic disorder patients but not in healthy controls. Different neurobiological vulnerabilities may be uncovered by different challenges and may indicate differential response to specific therapeutic interventions as well.

Keywords

• panic disorder
• CCK-4
• lactate
• acute panic inventory
• panicogenic activity