The modulation of neuronal activity by melatonin: In vitro studies on mouse hippocampal slices

Authors

  • M.V. Hogan,

    1. Department of Biology/CSI/IBR Center for Developmental Neuroscience, College of Staten Island/CUNY, 2800 Victory Boulevard, Staten Island, New York 10314, USA;
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  • Y. El-Sherif,

    1. Department of Biology/CSI/IBR Center for Developmental Neuroscience, College of Staten Island/CUNY, 2800 Victory Boulevard, Staten Island, New York 10314, USA;
    2. The Graduate School & University Center, the City University of NY, Ph.D. Program in Biology, Suite 4315, 365 Fifth Avenue, New York, New York 10016-4309
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  • A. Wieraszko

    1. Department of Biology/CSI/IBR Center for Developmental Neuroscience, College of Staten Island/CUNY, 2800 Victory Boulevard, Staten Island, New York 10314, USA;
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Address reprint requests to Dr. Andrzej Wieraszko, College of Staten Island/CUNY, 2800 Victory Boulevard, Staten Island, New York 10314, USA.
E-mail: Wieraszko@postbox.csi.cuny.edu

Abstract

The influence of melatonin on evoked potentials recorded from the CA1 field of mouse hippocampal slices was investigated. Melatonin (0.1–2.0 mM) and its analog, 6-chloromelatonin (0.1–0.5 mM) depressed evoked potentials (EPSP and the population spike) in a concentration-dependent manner. The melatonin-induced depression was followed by a slow recovery phase. Since the fiber potential was not affected, it was concluded that melatonin influenced synaptic efficiency and/or cell excitability. Luzindole, an antagonist of MT2 melatonin receptors, although slightly depressing evoked potentials when applied by itself (100 μM), blocked any further inhibition by melatonin when added afterwards. We concluded that melatonin reduced synaptic efficiency and/or excitability of hippocampal neurons most likely through interaction with MT2 melatonin receptors, but other possible mechanisms of melatonin action are also considered.

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