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Original Article |
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Neuropsychopharmacology (2002) 26 164-175.10.1038/S0893-133X(01)00299-8
Cocaine and Amphetamine Depress Striatal GABAergic Synaptic Transmission through D2 Dopamine Receptors
Diego Centonze1 MD, Barbara Picconi1 Ph.D, Christelle Baunez2 Ph.D, Emiliana Borrelli3 Ph.D, Antonio Pisani1 MD, Giorgio Bernardi1 MD and Paolo Calabresi1 MD |
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1Dipartimento di Neuroscienze, Clinica Neurologica, Università "Tor Vergata" and Fondazione Santa Lucia, IRCCS, Rome, Italy
2Laboratoire de Neurobiologie Cellulaire et Fonctionnelle, LNCF-CNRS UPR9013 Marseille, France
3Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS-INSERM-ULP, CU de Strasbourg, France
Correspondence: Prof Paolo, Calabresi, Clinica Neurologica, Dipartimento di Neuroscienze, Università di Tor Vergata, Via di Tor Vergata 135, Rome 00133, Italy; Tel.: +39-06-7259-6010; Fax: +39-06-7259-6006;calabre@uniroma2.it
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ABSTRACT
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The striatum is a brain area implicated in the pharmacological action of drugs of abuse. To test the possible involvement of both cocaine and amphetamine in the modulation of synaptic transmission in this nucleus, we coupled whole-cell patch clamp recordings from striatal spiny neurons to the focal stimulation of glutamatergic or GABAergic nerve terminals. We found that neither cocaine (1-600  M) nor amphetamine (0.3-300 M) significantly affected the glutamate-mediated EPSCs recorded from these cells. Conversely, both pharmacological agents depressed GABA-mediated IPSCs in a dose-dependent manner. This effect was mediated by the stimulation of dopamine (DA) D2 receptors since it was prevented by 3 M L-sulpiride (a DA D2-like receptor antagonist), mimicked by the DA D2-like receptor agonist quinpirole (0.3-30 M), and absent in mice lacking DA D2 receptors. A presynaptic mechanism was likely involved in this action since both cocaine and amphetamine depress GABAergic transmission by increasing paired-pulse facilitation. Cocaine and amphetamine failed to affect GABAergic IPSCs after 6-OHDA-induced nigral lesion, indicating that both drugs cause their effects through the release of endogenous DA. The modulation of GABAergic synaptic transmission in the striatum might underlie some motor and cognitive effects of psychostimulants in mammalians.
Keywords: Addiction; Basal ganglia; Electrophysiology; 6-OHDA; Medium spiny neurons; Psychostimulants; Transgenic mice |
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