Dopamine D4 Receptor-Induced Postsynaptic Inhibition of GABAergic Currents in Mouse Globus Pallidus Neurons

Ryong Moon Shin, Masao Masuda, Masami Miura, Hiromi Sano, Takuji Shirasawa, Wen Jie Song, Kazuto Kobayashi, Toshihiko Aosaki

Research output: Contribution to journalArticlepeer-review

62 Citations (Scopus)

Abstract

Dopamine D4 receptors (D4R) are localized in the globus pallidus (GP), but their function remains unknown. In contrast, dopamine D2 receptor activation hyperpolarizes medium spiny neurons projecting from the striatum to the GP and inhibits GABA release. However, using slice preparations from D2R-deficient [D2 knock-out (D2KO)] mice, we found that dopamine inhibited GABA A-receptor-mediated currents in GP neurons. The paired-pulse ratio was statistically unchanged after dopamine application but was significantly elevated in D2KO wild-type littermates (WT). Furthermore, in D2KO mice, outward currents elicited by iontophoretically applied GABA were suppressed by dopamine. Dopamine (30 μM) decreased the amplitude of miniature IPSCs in both WT and D2KO mice, but the decrease in the frequency was observed only in the former but not significantly in the latter. Dopamine-induced suppression of IPSCs was blocked by selective D4R antagonists (clozapine or 3-[4-(4-iodophenyl)piperazin-1-yl]methyl-1H-pyrrolo[2,3-b]pyridine trihydrochloride), and a D4R-selective agonist N-[[4-(2-cyanophenyl)-1-piperazinyl]methyl]-3-methyl]-3-methyl-benzamide reversibly and dose-dependently suppressed IPSCs, whereas agonists [SKF38,393 ((+/-)-1-phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol hydrochloride) or (+)(4aR,10bR)-3,4,4a,10b-tetrahydro-4-propyl-2H,5H-[1]benzopyrano[4,3-b]-1, 4-oxazin-9-ol] or antagonists [SCH23,390 (R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride) or sulpiride] of other receptor subtypes had little effect. In GP neurons from D4R-deficient mice, dopamine-induced inhibition of GABAergic outward currents was undetectable. D4R activation suppressed the activity of protein kinase A in GP neurons, resulting in a decrease in the amplitude of GABAergic IPSCs. These findings showed that postsynaptic activation of D4R on the GP neurons reduces GABAergic currents through the suppression of PKA activity.

Original languageEnglish
Pages (from-to)11662-11672
Number of pages11
JournalJournal of Neuroscience
Volume23
Issue number37
DOIs
Publication statusPublished - 17-12-2003
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)

Fingerprint

Dive into the research topics of 'Dopamine D4 Receptor-Induced Postsynaptic Inhibition of GABAergic Currents in Mouse Globus Pallidus Neurons'. Together they form a unique fingerprint.

Cite this