This observation laid the foundation for extensive research efforts on the experimental psychopathology of panic, which offers a unique opportunity in the field of psychiatry. The scientific and clinical promises of such symptom provocation studies for

the pathophysiology and psychopharmacology of psychiatric disorders have been drafted as follows3: In this paradigm investigators administer a psychopharmacologic agent or psychological challenge procedure to patients under controlled conditions to probe psychiatric symptoms and other neurobiological responses. The principal scientific rationale behind this approach is to learn more about the underlying pathophysiological Inhibitors,research,lifescience,medical mechanisms responsible for the symptomatic expression of psychiatric illnesses. In addition, the knowledge gained from this type of study might lead to better predictors of treatment response or identification of novel AVL-301 in vitro therapeutic interventions. A quintessential ethical framework of challenge studies

includes preserved decision-making capacity, informed consent, potential Inhibitors,research,lifescience,medical scientific and future clinical benefits, consent of an ethical committee, a favorable or acceptable Inhibitors,research,lifescience,medical risk:benefit ratio, absence of severe or long-lasting effects of the challenge agent, and follow-up studies on the effects of participation in symptom-provoking studies. In addition to lactate infusion, several further methods to provoke experimental panic attacks in patients with panic disorder by pharmacological means have been developed during the past decades (overview in ref 4). These display many different modes of action and have different targets. They include other agents that influence respiration, such as carbon dioxide inhalation or doxapram infusion. Further established panicogens Inhibitors,research,lifescience,medical act specifically on neurotransmission, such as the noradrenergic substances yohimbine and isoprenaline, Inhibitors,research,lifescience,medical the serotonergic agents metachlorophenylpiperazine (mCPP) and fenfluramine, benzodiazepine-receptor agents, such as the inverse agonist FG 7142 and the antagonist flumazenil, agonists at the CCK-2 (formerly type B) receptor, such as cholecystokinin

tetrapeptide (CKK-4) and pentagastrin, and the adenosine receptor antagonist caffeine. The following criteria for an ideal panicogen for human use have been proposed (compiled according to Gutmacher et al5 and Gorman et al6): It should be safe It should mimic naturally occurring panic attacks It should foster both central and peripheral Dichloromethane dehalogenase manifestations of panic It should be replicable The phenomena should be either short-lived or readily reversible It should differentiate between healthy subjects and those with pathology It should reflect the potential for a state response; those who have been successfully treated clinically should not respond or respond far less than those who have had no treatment The effects should not be blocked by drugs, which do not work against spontaneous panic.