• Many clinical and theoretic attempts have been made to link anxiety disorders and the ß-adrenergic nervous system. Six patients with panic disorder, who had panic attacks produced by sodium lactate infusions, were given repeated lactate infusions that were immediately preceded by intravenous administration of propranolol hydrochloride. In all cases, propranolol pretreatment infusion failed to prevent panic attacks, anxiety, tachycardia, and increased systolic BP during the lactate infusion.