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N-Acetylaspartylglutamate Stimulates Metabotropic Glutamate Receptor 3 to Regulate Expression of the GABAAα6 Subunit in Cerebellar Granule Cells
- Source :
- Journal of Neurochemistry. 69:2326-2335
- Publication Year :
- 2002
- Publisher :
- Wiley, 2002.
-
Abstract
- We have shown that the vertebrate neuropeptide N-acetylaspartylglutamate (NAAG) meets the criteria for a neurotransmitter, including function as a selective metabotropic glutamate receptor (mGluR) 3 agonist. Short-term treatment of cerebellar granule cells with NAAG (30 microM) results in the transient increase in content of GABA(A) alpha6 subunit mRNA. Using quantitative PCR, this increase was determined to be up to 170% of control values. Similar effects are seen following treatment with trans-1-aminocyclopentane-1,3-dicarboxylate and glutamate and are blocked by the mGluR antagonists (2S,3S,4S)-2-methyl-2-(carboxycyclopropyl) glycine and (2S)-alpha-ethylglutamic acid. The effect is pertussis toxin-sensitive. The increase in alpha6 subunit mRNA level can be simulated by activation of other receptors negatively linked to adenylate cyclase activity, such as adenosine A1, alpha2-adrenergic, muscarinic, and GABA(B) receptors. Forskolin stimulation of cyclic AMP (cAMP) levels abolished the effect of NAAG. The change in alpha6 levels induced by 30 microM NAAG can be inhibited in a dose-dependent manner by simultaneous application of increasing doses of the beta-adrenergic receptor agonist isoproterenol. The increase in alpha6 mRNA content is followed by a fourfold increase in alpha6 protein level 6 h posttreatment. Under voltage-clamped conditions, NAAG-treated granule cells demonstrate an increase in the furosemide-induced inhibition of GABA-gated currents in a concentration-dependent manner, indicating an increase in functional alpha6-containing GABA(A) receptors. These data support the hypothesis that NAAG, acting through mGluR3, regulates expression of the GABA(A) alpha6 subunit via a cAMP-mediated pathway and that cAMP-coupled receptors for other neurotransmitters may similarly influence GABA(A) receptor subunit composition.
- Subjects :
- Agonist
medicine.medical_specialty
Transcription, Genetic
medicine.drug_class
Biology
Receptors, Metabotropic Glutamate
Polymerase Chain Reaction
Biochemistry
Rats, Sprague-Dawley
Cellular and Molecular Neuroscience
chemistry.chemical_compound
Furosemide
Cerebellum
Internal medicine
Muscarinic acetylcholine receptor
Cyclic AMP
medicine
Animals
RNA, Messenger
Receptor
Cells, Cultured
gamma-Aminobutyric Acid
Neurons
Metabotropic glutamate receptor • mGluR3 • Glutamate • N-Acetylaspartylglutamate • GABAA receptor • GABAAα6 • Cyclic AMP • Cerebellar granule cells • mRNA regulation
Forskolin
GABAA receptor
Colforsin
Electric Conductivity
Glutamate receptor
Dipeptides
Receptors, GABA-A
Rats
Endocrinology
chemistry
Metabotropic glutamate receptor
Metabotropic glutamate receptor 3
Ion Channel Gating
Subjects
Details
- ISSN :
- 14714159 and 00223042
- Volume :
- 69
- Database :
- OpenAIRE
- Journal :
- Journal of Neurochemistry
- Accession number :
- edsair.doi.dedup.....ef3416fc771d2cc32640ba288f25883e