Screening antidepressants in the chick separation-stress paradigm.
BACKGROUND
Clinical research has indicated that antidepressants are efficacious in the treatment of anxiety disorders, especially when repeatedly administered. However, few animal models of anxiety are sensitive to antidepressants, a finding that may be due to procedures limited to acute administrations.


OBJECTIVE
The purpose of the present research was to further validate the chick separation-stress paradigm as an animal model of anxiety by examining its sensitivity to the monoamine oxidase inhibitor (MAOI) phenelzine (6.25, 12.5, 25.0 mg/kg), the tricyclic antidepressant (TCA) imipramine (5.0, 10.0, 20.0 mg/kg), the selective serotonin reuptake inhibitor (SSRI) citalopram (1.0, 2.5, 5.0 mg/kg), and the norepinephrine reuptake inhibitor (NRI) maprotiline (5.0, 10.0, 20.0 mg/kg) under acute (no pretreatment) or repeated (3 or 6 days pretreatment) administration procedures.


METHODS
Following any pretreatment, 8-day-old chicks received their respective vehicle or drug probe injection 15 min before tests in either a "mirror" (low stress) or "no mirror" (high stress) condition for a 180-s isolation period. The dependent measures were distress vocalizations to index separation stress and sleep onset latency to index sedation.


RESULTS
The model was sensitive to acutely administered phenelzine (MAOI), imipramine (TCA), and maprotiline (NRI), but not citalopram (SSRI) and retained its sensitivity to these drug probes across both repeated administration procedures. None of the drug probes possessed any sedative properties.


CONCLUSIONS
These results help extend the validity and utility of the chick separation-stress paradigm as an animal model of anxiety by demonstrating its sensitivity to antidepressants under both acute and repeated administration procedures.
Feltenstein
Matthew W
MW
Department of Psychology, University of Mississippi, Oxford, MS 38677, USA. feltens@musc.edu
Sufka
Kenneth J
KJ
D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D001010:Anxiety, Separation / Q000188:drug therapy*; D002645:Chickens; D015283:Citalopram / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical / Q000191:economics / Q000379:methods*; D007099:Imipramine / Q000494:pharmacology; D008376:Maprotiline / Q000494:pharmacology; D010624:Phenelzine / Q000494:pharmacology; D012893:Sleep Wake Disorders / Q000209:etiology; D013315:Stress, Psychological / Q000188:drug therapy
D000928:Antidepressive Agents; D015283:Citalopram; D008376:Maprotiline; D010624:Phenelzine; D007099:Imipramine