Acute stress induced modifications of calcium signaling in learned helpless rats

Pharmacopsychiatry. 2000 Jul;33(4):132-7. doi: 10.1055/s-2000-11220.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Avoidance Learning / physiology*
  • Calcium Signaling / physiology*
  • Corticosterone / blood
  • Electroshock
  • Helplessness, Learned*
  • Male
  • Rats
  • Rats, Wistar
  • Spleen / immunology
  • Stress, Psychological / physiopathology*
  • T-Lymphocytes / physiology*


  • Corticosterone