The present study examined the electrophysiological effects produced by activation of specific dopamine (DA) receptors and the distribution of DA receptor subtypes and glutamate receptor subunits [N-methyl-D-aspartate (NMDAR1) and GluR1] in cortical tissue samples obtained from children (ages 3 months to 16 years) undergoing epilepsy surgery. DA receptor activation produced differential effects depending on the receptor subtype that was activated. D1 receptor family agonists generally enhanced cortical excitability and favored the emergence of epileptogenic activity. In contrast, D2 receptor family agonists had more variable effects on cortical excitability and the expression of epileptiform discharges. Activation of D1 or D2 receptors decreased the amplitude of non-NMDA-mediated excitatory postsynaptic potentials. In contrast, DA and D1 agonists increased the amplitude of NMDA-mediated potentials. Immunohistochemical analysis showed that the DA receptor subtypes and glutamate receptor subunits examined were present in all cortical layers and areas throughout development. Whole-cell voltage clamp recordings of pyramidal neurons visualized with differential interference contrast optics and infrared videomicroscopy indicated that these neurons displayed a persistent Na+ current, followed by an outward current. DA reduced the outward current but had little effect on the persistent Na+ current. These results suggest a dual role for DA’s actions in the human cerebral cortex. Activation of D2 receptors or antagonism of D1 receptors may help control seizures in children.
Michael S. Levine, PhD
Mental Retardation Research Center, 760 Westwood Plaza, Room 58-258 NPI
UCLA School of Medicine
Los Angeles, CA 90024 (USA)
Tel. +1 310 825 7595, Fax +1 310 206 5060, E-Mail firstname.lastname@example.org
Received: Received: April 30, 1999
Accepted: May 5, 1999
Number of Print Pages : 13
Number of Figures : 9, Number of Tables : 0, Number of References : 71
Vol. 21, No. 3-5, Year 1999 (Cover Date: May-October 1999 (Released November 1999))
Journal Editor: A.T. Campagnoni, Los Angeles, Calif.
ISSN: 0378–5866 (print), 1421–9859 (Online)
For additional information: http://www.karger.com/journals/dne
Article / Publication Details
Published online: 4/29/2011
Issue release date: May–October 1999 (November 1999)
Number of Print Pages: 13
Number of Figures: 9
Number of Tables: 0
ISSN: 0378-5866 (Print)
eISSN: 1421-9859 (Online)
For additional information: http://www.karger.com/DNE
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