Peer Reviewed

1

Document Type

Article

Publication Date

6-2008

Keywords

2, 3, 4, 5-Tetrahydro-7, 8-dihydroxy-1-phenyl-1H-3-benzazepine, Animals, Benzazepines, Corpus Striatum, Dopamine and cAMP-Regulated Phosphoprotein 32, Dose-Response Relationship, Drug, Electroencephalography, Hippocampus, Mice, Mice, Inbred C57BL, Mice, Knockout, Mitogen-Activated Protein Kinase 3, Phosphorylation, Reaction Time, Receptors, AMPA, Receptors, Dopamine D1, Receptors, Dopamine D5, Seizures, Signal Transduction, Threonine, Time Factors

Comments

This article is available from Elsevier at http://www.sciencedirect.com. Please see additional files (Table and Figures) below.

Abstract

Recent reports have shown that the selective dopamine D(1)-like agonist SKF 83822 [which stimulates adenylate cyclase, but not phospholipase C] induces prominent behavioral seizures in mice, whereas its benzazepine congener SKF 83959 [which stimulates phospholipase C, but not adenylate cyclase] does not. To investigate the relative involvement of D(1) vs D(5) receptors in mediating seizures, ethological behavioral topography and cortical EEGs were recorded in D(1), D(5) and DARPP-32 knockout mice in response to a convulsant dose of SKF 83822. SKF 83822-induced behavioral and EEG seizures were gene dose-dependently abolished in D(1) knockouts. In both heterozygous and homozygous D(5) knockouts, the latency to first seizure was significantly increased and total EEG seizures were reduced relative to wild-types. The majority (60%) of homozygous DARPP-32 knockouts did not have seizures; of those having seizures (40%), the latency to first seizure was significantly increased and the number of high amplitude, high frequency polyspike EEG events was reduced. In addition, immunoblotting was performed to investigate downstream intracellular signalling mechanisms at D(1)-like receptors following challenge with SKF 83822 and SKF 83959. In wild-types administered SKF 83822, levels of ERK1/2 and GluR1 AMPA receptor phosphorylation increased two-fold in both the striatum and hippocampus; in striatal slices DARPP-32 phosphorylation at Thr34 increased five-fold relative to vehicle-treated controls. These findings indicate that D(1), and to a lesser extent D(5), receptor coupling to DARPP-32, ERK1/2 and glutamatergic signalling is involved in mediating the convulsant effects of SKF 83822.

Disciplines

Life Sciences

Citation

O'Sullivan GJ, Dunleavy M, Hakausson K, Clementi M, Kinsella A, Croke DT, Drago J, Fienberg P, Sibley DR, Fisone G, Henshall DC, Waddington JL. Dopamine D1 vs D5 receptor-dependent induction of seizures in relation to DARPP-32, ERK1/2 and GluR1-AMPA signalling. Neuropharmacology 2008;54(7):1051-61.

PubMed ID

18367215

DOI Link

10.1016/j.neuropharm.2008.02.011

Table1_OSullivan.pdf (17 kB)
Table 1 O'Sullivan et al

Figures_OSullivan_etal.pdf (536 kB)
Figures O'Sullivan et al

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