Selective Corticosteroid Antagonists Modulate Specific Aspects of Spatial Orientation Learning

Receptors for mineralocorticoids (MRs) and glucocorticoids (GRs) display a high concentration and distinct distribution in the hippocampus. The effects of corticosteroids on behavior mediated by central MRs and GRs were assessed in rats. Spatial navigation is considered to be a sensitive measure for hippocampal functioning. Removal of circulating corticosteroids (via adrenalectomy) impaired spatial learning. In intact rats, blockade of central MRs and GRs by intracerebroventricular injection of selective MR and GR antagonists influenced different aspects of spatial learning. The analysis of the behavioral pattern revealed that treatment with the MR antagonist altered search-escape strategies in the water maze. The injection of the GR antagonist after training resulted in increased latencies to find the platform, which reflects the disturbed consolidation of spatial information. Corticosteroids affect in a differential and coordinated manner behavioral strategies and storage of spatial information.