Brief neck restraint stress enhances long-term potentiation and suppresses long-term depression in the dentate gyrus of the mouse.

We studied the effects of brief (10 min) neck restraint on long-term potentiation (LTP) and long-term depression (LTD) in mouse dentate gyrus (DG) slices. Brain slices were prepared immediately after neck restraint and LTP/LTD induction was attempted 3.5h later. LTP enhancement and LTD suppression was observed in slices prepared from stressed animals. The corticosterone plasma concentration was elevated approx. fourfold just after the neck restraint session. To examine the role of glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) activation in mediating the effects of neck restraint on LTP and LTD, the animals were pretreated with either the specific GR antagonist RU38486, the specific MR antagonist spironolactone, the corticosterone synthesis inhibitor metyrapone, or vehicle Tween 80. Injection with Tween 80 and subsequent neck restraint did not influence LTP enhancement or LTD suppression, but the effects of neck restraint were prevented by RU38486, spironolactone and metyrapone pretreatment. These data indicate that acute stress caused by brief neck restraint enhances LTP and impairs LTD in the dentate gyrus and that these effects are mediated by activation of GRs and MRs.