The Journal of Neuroscience, July 8, 2009, 29(27):8633-8638; doi:10.1523/JNEUROSCI.1901-09.2009
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Brief Communications
Differential Modulation of Long-Term Depression by Acute Stress in the Rat Dorsal and Ventral Hippocampus
Nicola Maggio and
Menahem Segal
Department of Neurobiology, The Weizmann Institute, 76100 Rehovot, Israel
Correspondence should be addressed to Nicola Maggio at the above address. Email: nicola.maggio{at}weizmann.ac.il
The ventral hippocampus (VH) was recently shown to express lower-magnitude long-term potentiation (LTP) than the dorsal hippocampus (DH). An exposure to acute stress reversed this difference, and VH slices from stressed rats expressed larger LTP than controls, whereas LTP in the DH was suppressed by stress. We have now used long-term depression (LTD)-generating trains of stimulation to examine whether this differential LTP reflects a genuine difference in synaptic modifiability between the two sectors of the hippocampus. Surprisingly, slices of DH and VH express similar magnitudes of LTD. However, while prior stress enhanced LTD in the DH, it actually converted LTD to slow-onset, robust LTP in the VH. These two effects of stress on LTD were blocked by glucocorticosterone receptor (GR) and mineralocorticosterone receptor (MR) antagonists, respectively. Acute exposure of slices to a GR agonist dexamethasone facilitated LTD in slices of both DH and VH, while activation of MRs by aldosterone converted LTD to LTP in both regions. Thus, differential activation of the two species of corticosterone receptors determines the ability of the two sectors of the hippocampus to undergo plastic changes in response to LTD-inducing stimulation.
Received April 22, 2009;
revised May 21, 2009;
accepted May 22, 2009.
Correspondence should be addressed to Nicola Maggio at the above address. Email: nicola.maggio{at}weizmann.ac.il
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