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Melatonin interaction with magnesium and zinc in the response of the striatum to sensorimotor cortical stimulation in the rat
Author(s) -
Eseames G.,
AcunaCastroviejo D.,
Lebn J.,
Vives F.
Publication year - 1998
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/j.1600-079x.1998.tb00377.x
Subject(s) - nmda receptor , glutamate receptor , excitatory postsynaptic potential , stimulation , striatum , inhibitory postsynaptic potential , excitotoxicity , endocrinology , medicine , chemistry , melatonin , glutamatergic , neuroscience , receptor , biology , biochemistry , dopamine
Eseames G, Acuña‐Castroviejo D, León J, Vives F. Melatonin interaction with magnesium and zinc in the response of the striatum to sensorimotor cortical stimulation in the rat. J. Pineal Res. 1998; 24:123–129. © Munksgaard, Copenhagen Abstract The sensorimotor cortex (SMCx) sends numerous projections to the striatum. These projections are excitatory and glutamate mediated. Glutamatergic receptors, specifically those of NMDA type‐receptors, are closely related to excitotoxicity. Thus, in some circumstances, an excess of Ca 2+ influx through NMDA channels alters neuronal metabolism and may become lethal for the cell. Two other divalent cations, Mg 2+ and Zn 2+ , have inhibitory effects on NMDA receptors. Magnesium ions exert a voltage‐dependent block of the NMDA calcium channel, whereas zinc ions exert a voltage‐independent NMDA block. In the present work, the effects of iontophoresis of Mg 2+ and Zn 2+ on the striatal response to SMCx stimulation were studied. Moreover melatonin, an indoleamine with anticonvulsant properties and inhibitory effects on the NMDA receptor, was also iontophorized alone or in combination with Mg 2+ and Zn 2+ . Single pulse electrical stimulation of SMCx produced an excitatory response in the striatum. Iontophoresis of melatonin, Mg 2+ and Zn 2+ produced a potent attenuation of the excitatory response of the striatum to SMCx stimulation, although the latency of the effect of melatonin was longer than those of Mg 2+ and Zn 2+ . When these cations were simultaneously ejected with melatonin, additive inhibitory effects were recorded. These observations suggest that the inhibitory effects produced by Mg 2+ and Zn 2+ and melatonin are produced via different processes, and thus the inhibitory role of melatonin on the NMDA receptor activity is exclusive of a direct action on the NMDA calcium channel.