title: Acute stress induced modifications of calcium signaling in learned helpless rats.
abstract: Previous reports have demonstrated reduced elevations of free intracellular calcium concentration in blood cells of depressed patients after various stimuli. Therefore, a disturbance of intracellular calcium (Ca2+) homeostasis has been postulated to be involved in the pathophysiology of mood disorders. It was the aim of the present study to investigate whether Ca2+ signaling was affected in spleen T-lymphocytes of rats submitted to a learned helplessness paradigm, an animal model of depression with a high level of construct, face and predictive validity. In addition, we tested for effects of acute stress on the Ca2+ signaling in helpless rats, as compared to non-stressed rats. It was found that mitogen-induced Ca2+ signaling only tended to be reduced in helpless rats. However, when helpless rats were submitted to acute immobilization stress, Ca2+ signaling appeared to be significantly blunted, whereas the same stressor did not affect Ca2+ signaling in the non-helpless control rats. These acute stress-induced differences in Ca2+ signaling were not paralleled by a differential increase in plasma corticosterone. It is hypothesized that blunted Ca2+ signaling, as assessed in spleen T-lymphocytes of helpless rats, may be a correlate of the increased vulnerability of helpless rats to acute stressors.
authors.affiliation: Central Institute of Mental Health, Department of Psychopharmacology and Psychiatry, Mannheim, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Velbinger
authors.forename: J
authors.initials: J
authors.lastname: De Vry
authors.forename: K
authors.initials: K
authors.lastname: Jentzsch
authors.forename: A
authors.initials: A
authors.lastname: Eckert
authors.forename: F
authors.initials: F
authors.lastname: Henn
authors.forename: W E
authors.initials: WE
authors.lastname: Müller
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000502:physiology*; D020013:Calcium Signaling / Q000502:physiology*; D003345:Corticosterone / Q000097:blood; D004597:Electroshock; D006380:Helplessness, Learned; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013154:Spleen / Q000276:immunology; D013315:Stress, Psychological / Q000503:physiopathology*; D013601:T-Lymphocytes / Q000502:physiology*
chemical_list: D003345:Corticosterone