Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9723299 | Neurobiology of Learning and Memory | 2005 | 7 Pages |
Abstract
Growing evidence suggests that processes of synaptic plasticity, such as long-term potentiation (LTP) occurring in one synaptic population, can be modulated by consolidating afferents from other brain structures. We have previously shown that an early-LTP lasting less than 4Â h (E-LTP) in the dentate gyrus can be prolonged by stimulating the basolateral amygdala, the septum or the locus coeruleus within a specific time window. Pharmacological experiments have suggested that noradregeneric (NE) and/or cholinergic systems might be involved in these effects. We have therefore investigated whether the direct intraventricular application of agonists for NE- or muscarinic receptors is able to modulate synaptic plasticity. E-LTP was induced at the dentate gyrus of freely moving rats using a mild tetanization protocol that induces only an E-LTP. NE or oxotremorine (OXO) were applied icv 10Â min after the tetanus. Results show that low doses of NE (1.5 and 5Â nM) effectively prolong LTP. A higher dose (50Â nM) was not effective. None of the OXO doses employed (5, 25, and 50Â nM) showed similar effects. These results stress the importance of transmitter-specific modulatory influences on the time course of synaptic plasticity, in particular NE whose application mimics the reinforcing effect of directly stimulating limbic structures on LTP.
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Authors
William Almaguer-Melian, Yeneissy Rojas-Reyes, Armando Alvare, Juan C. Rosillo, Julietta U. Frey, Jorge A. Bergado,