Pulmonary and systemic nitric oxide measurements during CCK-5-induced panic attacks.

Nitric oxide (NO) plays a major role in cardiopulmonary regulation as illustrated by the alterations of the NO system described in cardiopulmonary illnesses. Recent studies have found an association between panic disorder and cardiovascular death and illness, as well as pulmonary diseases. Our objective was to investigate whether pulmonary or systemic NO production was altered during induced panic attacks (PAs). We used a double-blind placebo-controlled crossover design with randomization of the order of an injection of placebo and pentagastrin, a cholecystokinin-B receptor agonist that induces PAs in healthy volunteers (HVs). A total of 17 HVs experienced a PA after pentagastrin challenge. Exhaled NO and NO metabolites were measured by chemiluminescence. During pentagastrin-induced PAs, HVs displayed significant decreases in plateau concentrations of NO exhaled, which were associated with proportional increases in minute ventilation. There were no significant changes in pulmonary or systemic NO production. These results suggest that the decrease in exhaled NO concentration observed during pentagastrin-induced PAs is related to the associated hyperventilation, rather than to any change in lung NO production. This study is the first to evaluate changes in NO measurements during acute anxiety.