Chronic corticosterone impairs inhibitory avoidance in rats: possible link with atrophy of hippocampal CA3 neurons

V. BISAGNO; M. FERRINI; H. RIOS; L.M. ZIEHER; S.I. WIKINSKI

PHARMACOLOGY BIOCHEMISTRY AND BEHAVIOR

Elsevier

Lugar: New York; Año: 2000 p. 235 - 240

0091-3057

The aim of our work was to evaluate the effect of a chronic (22 days) administration of corticosterone, which induces supraphysiological serum lever of the hormone, on an inhibitory avoidance learning in rats (one-trial step-through learning task, footshock 0.5 mA, 2s). We also studied hippocampal markers of neuroanatomical CA3 pyramidal neurons atrophy by using the Golgi staining method. Chronic exposure to high CORT serum levels induced a significant impairment of inhibitory avoidance learning. The CORT group also showed hippocampal glucocorticoid receptor (GR) downregulation and the decrease of CA3 branch points and total dendritic length in the apical tree that would be casually related with the learning impairment.