title: Prevention of learned helplessness: in vivo correlation with cortical serotonin.
abstract: Learned helplessness (LH) is prevented by pretreatment with acute benzodiazepines (BDZs), subchronic tricyclic antidepressants (TCAs), or escapable stress (ES). We have investigated the role of serotonin (5-HT) in LH prevention by these three prevention paradigms, using microdialysis to measure in vivo 5-HT release in frontal cortex (FC) after LH testing. Rats receiving pretreatment before inescapable stress with any of the three methods of prevention--BDZs, TCAs, or ES--showed escape behavior in the shuttle-box test for LH comparable to naive unstressed controls. K(+)-stimulated 5-HT release in all three groups receiving pretreatment was also similar to naive unstressed controls. Rats receiving saline before inescapable stress showed significantly more LH behavior in the shuttle-box task and had significantly lower 5-HT release as well. This suggests that LH correlates with a significant decrease in intracellular releasable 5-HT in FC, and that three different techniques for LH prevention, acute BDZs, subchronic TCAs, and ES all similarly prevent this 5-HT depletion.
authors.affiliation: Psychiatry Service (116A), Veterans Affairs Medical Center, Dallas, TX 75216.
authors.forename: F
authors.initials: F
authors.lastname: Petty
authors.forename: G
authors.initials: G
authors.lastname: Kramer
authors.forename: L
authors.initials: L
authors.lastname: Wilson
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002540:Cerebral Cortex / Q000378:metabolism*; D003956:Dialysis; D003975:Diazepam / Q000494:pharmacology; D004597:Electroshock; D006380:Helplessness, Learned; D007099:Imipramine / Q000494:pharmacology; D008297:Male; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D012701:Serotonin; D013779:Tetrodotoxin; D007099:Imipramine; D003975:Diazepam; D011188:Potassium