Indirect presynaptic modulation of striatal dopamine release by GABA(B) receptors in the rat substantia nigra

• Published in: Neuroscience letters Vol. 325; no. 1; pp. 33 - 36
• Main Authors: Balon, Norbert, Kriem, Badreddine, Weiss, Michel, Rostain, Jean-Claude
• Format: Journal Article
• Language: English
• Published: Ireland 31-05-2002
• Subjects: Amino Acids, Neutral - pharmacology; Animals; Baclofen - pharmacology; Corpus Striatum - metabolism; Dopamine - metabolism; Electrophysiology; GABA Agonists - pharmacology; GABA Antagonists - pharmacology; GABA-B Receptor Agonists; Male; Presynaptic Terminals - physiology; Rats; Rats, Sprague-Dawley; Receptors, GABA-B - physiology; Substantia Nigra - metabolism
• ISSN: 0304-3940
• DOI: 10.1016/S0304-3940(02)00226-4

Regulation of striatal dopamine release by gamma-aminobutyric acid (GABA) neurotransmission was investigated using voltammetry in freely moving rats, following focal injection of the GABA(B) receptor agonist baclofen or the GABA(B) receptor antagonist 5-aminovaleric acid (5-AVA) in either the substantia nigra pars reticulata (SNr) or the substantia nigra pars compacta (SNc). Administration in the SNr of baclofen and 5-AVA at the dose of 2 pg, but not of 0.2 pg, resulted in a decrease and an increase in striatal dopamine release, respectively. In contrast, when injected in the SNc, 5-AVA only produced a transient increase in striatal dopamine release, while baclofen remained ineffective. This suggests that GABA(B) receptors in the SNr, but not the SNc, may play a major role in the control of nigrostriatal dopamine (DA) activity and the release of DA in the striatum.