Treatment with escitalopram but not desipramine decreases escape latency times in a learned helplessness model using juvenile rats.
BACKGROUND
The pharmacological treatment of depression in children and adolescents is different from that of adults due to the lack of efficacy of certain antidepressants in the pediatric age group. Our current understanding of why these differences occur is very limited.


OBJECTIVE
To develop more effective treatments, a juvenile animal model of depression was tested to validate it as a possible model to specifically study pediatric depression.


METHODS
Procedures for use with juvenile rats at postnatal day (PND) 21 and 28 were adapted from the adult learned helplessness model in which, 24 h after exposure to inescapable stress, animals are unable to remove themselves from an easily escapable stressor. Rats were treated for 7 days with either the selective serotonin reuptake inhibitor escitalopram at 10 mg/kg or the tricyclic antidepressant desipramine at 3, 10, or 15 mg/kg to determine if treatment could decrease escape latency times.


RESULTS
Escitalopram treatment was effective at decreasing escape latency times in all ages tested. Desipramine treatment did not decrease escape latency times for PND 21 rats, but did decrease times for PND 28 and adult animals.


CONCLUSIONS
The learned helplessness model with PND 21 rats predicts the efficacy of escitalopram and the lack of efficacy of desipramine seen in the treatment of pediatric depression. These findings suggest that the use of PND 21 rats in a modified learned helplessness procedure may be a valuable model of human pediatric depression that can predict pediatric antidepressant efficacy and be used to study antidepressant mechanisms involved in pediatric depression.
Reed
Abbey L
AL
Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, 985800 Nebraska Medical Center, Omaha, NE 68198-5800, USA. amaul@unmc.edu
Anderson
Jeffrey C
JC
Bylund
David B
DB
Petty
Frederick
F
El Refaey
Hesham
H
Happe
H Kevin
HK
D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D018687:Antidepressive Agents, Second-Generation / Q000494:pharmacology*; D000929:Antidepressive Agents, Tricyclic / Q000494:pharmacology; D001703:Biophysics; D015283:Citalopram / Q000494:pharmacology*; D003891:Desipramine / Q000494:pharmacology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004597:Electroshock; D004924:Escape Reaction / Q000187:drug effects*; D006380:Helplessness, Learned; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects*
D018687:Antidepressive Agents, Second-Generation; D000929:Antidepressive Agents, Tricyclic; D015283:Citalopram; D003891:Desipramine