Lesion of the bed nucleus of the stria terminalis enhances learned despair.
ABSTRACT The bed nucleus of the stria terminalis (BNST) was lesioned in adult male Wistar rats (n = 9) and its involvement in coping behavior during forced swim stress examined. Rats remain immobile longer in the second of two swim tests, a phenomenon known as learned despair. Results revealed that, compared to sham-operated controls (n = 8), BNST-lesioned animals displayed immobility significantly earlier and for longer durations in the second swim test. Rats with BNST lesions also showed significantly reduced escape behavior in the form of fewer numbers of jumps and dives compared to controls. Mobility deficits were not due to general motor impairment as revealed by an open field test. Results suggest that the BNST may modulate coping behavior especially during uncontrollable stress.
[show abstract] [hide abstract]
ABSTRACT: The bed nucleus of the stria terminalis (BNST) is a basal forebrain structure involved in many motivational processes closely linked to stress regulation. The present study investigated the effect of bilateral lesions of the BNST in male Wistar rats on behavioral despair and navigational learning in the Morris water maze both of which present stressful challenges. Compared to controls, BNST-lesioned animals displayed longer duration of immobility in the second of two forced swim tests used to assess behavioral despair but performed similarly in the water maze task. The present results indicate strongly that the BNST is involved in the modulation of behavioral despair. Experimentally induced depression by BNST lesions does not impair learning and memory in the water maze suggesting a possible dissociation between BNST-mediated depression and cognitive performance.Brain Research Bulletin 05/2006; 69(4):416-21. · 2.82 Impact Factor
Article: Acute reversible inactivation of the bed nucleus of stria terminalis induces antidepressant-like effect in the rat forced swimming test.[show abstract] [hide abstract]
ABSTRACT: The bed nucleus of stria terminalis (BNST) is a limbic forebrain structure involved in hypothalamo-pituitary-adrenal axis regulation and stress adaptation. Inappropriate adaptation to stress is thought to compromise the organism's coping mechanisms, which have been implicated in the neurobiology of depression. However, the studies aimed at investigating BNST involvement in depression pathophysiology have yielded contradictory results. Therefore, the objective of the present study was to investigate the effects of temporary acute inactivation of synaptic transmission in the BNST by local microinjection of cobalt chloride (CoCl2) in rats subjected to the forced swimming test (FST). Rats implanted with cannulae aimed at the BNST were submitted to 15 min of forced swimming (pretest). Twenty-four hours later immobility time was registered in a new 5 min forced swimming session (test). Independent groups of rats received bilateral microinjections of CoCl2 (1 mM/100 nL) before or immediately after pretest or before the test session. Additional groups received the same treatment and were submitted to the open field test to control for unspecific effects on locomotor behavior. CoCl2 injection into the BNST before either the pretest or test sessions reduced immobility in the FST, suggesting an antidepressant-like effect. No significant effect of CoCl2 was observed when it was injected into the BNST immediately after pretest. In addition, no effect of BNST inactivation was observed in the open field test. These results suggest that acute reversible inactivation of synaptic transmission in the BNST facilitates adaptation to stress and induces antidepressant-like effects.Behavioral and Brain Functions 01/2010; 6:30. · 2.13 Impact Factor