Vasopressin response to lactate infusion in normals and patients with panic disorder.

Infusions of sodium lactate evoke panic symptoms in patients with panic disorder but not in normal subjects. Although plasma vasopressin (AVP) is known to rise in response to other forms of stress, its response during this maneuver has not previously been reported. We measured plasma AVP in double-blind infusions of sodium lactate in 5 normal subjects, 6 patients with panic disorder, and, again in 4 patients after chronic alprazolam. In all groups administered lactate, AVP rose significantly above baseline values (p less than 0.05) though no change was seen in a control group of patients during D5NS infusion. No difference in AVP response to lactate was apparent between untreated patients (who experienced panic) and normals or chronically treated patients (who had minimal symptoms). Thus, the presence of panic symptoms induced by lactate is insufficient to provoke an abnormal pattern of AVP release.