Effects of acute and chronic anti-panic drug administration on conflict behavior in the rat.

The present studies were undertaken to evaluate further the utility of the Conditioned Suppression of Drinking (CSD) conflict paradigm as an animal model for the study of panic disorder and anti-panic agents. In daily 10-min sessions, water-deprived rats were trained to drink from a tube which was occasionally electrified (0.5 mA). Electrification was signalled by a tone. Desipramine (DMI), amitriptyline (AMI), or phenelzine (PHEN) was administered both in acute (10-min pre-treatment) and chronic (twice daily for up to 9 weeks) regimens. Acute administration of DMI, AMI or PHEN over a wide range of doses resulted in no change or a decrease in the number of shocks accepted and a decrease in water intake at higher doses. In contrast, chronic administration of each agent resulted in a gradual (2-4 week latency) increase in the number of shocks received in CSD sessions over the course of several weeks of testing. This time-dependent increase in punished responding in the CSD observed during chronic anti-panic drug treatment parallels the time-dependent reduction in the severity and frequency of panic attacks in panic disorder patients receiving chronic antidepressants. Thus, the CSD paradigm might serve as an animal model for the study of panic disorder and potential anti-panic agents.