Dopamine Receptor Subtypes Modulate Olfactory Bulb γ -aminobutyric acid Type A Receptors

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 96; no. 5; pp. 2456 - 2460
• Main Authors: Brunig, Ina, Sommer, Michael, Hatt, Hanns, Bormann, Joachim
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 02.03.1999; National Acad Sciences; National Academy of Sciences; The National Academy of Sciences
• Subjects: 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine - pharmacology; Amacrine cells; Animals; Biological Sciences; Brain; Bromocriptine - pharmacology; Cells, Cultured; Cholera Toxin - pharmacology; Cyclic AMP - pharmacology; Cyclic AMP-Dependent Protein Kinases - metabolism; Dopamine - pharmacology; Dopamine receptors; Dose response relationship; Embryo, Mammalian; GABA receptors; gamma-Aminobutyric Acid - pharmacology; Mammals; Neurology; Neurons; Neurons - classification; Neurons - cytology; Neurons - physiology; Neuroscience; Olfactory bulb; Olfactory Bulb - physiology; Phosphorylation; Pipettes; Protein Kinase C - metabolism; Proteins; Rats; Receptors; Receptors, Dopamine D1 - drug effects; Receptors, Dopamine D1 - physiology; Receptors, Dopamine D2 - drug effects; Receptors, Dopamine D2 - physiology; Receptors, GABA-A - drug effects; Receptors, GABA-A - physiology
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.96.5.2456

The γ -aminobutyric acid type A (GABAA) receptor is the predominant Cl-channel protein mediating inhibition in the olfactory bulb and elsewhere in the mammalian brain. The olfactory bulb is rich in neurons containing both GABA and dopamine. Dopamine D1 and D2 receptors are also highly expressed in this brain region with a distinct and complementary distribution pattern. This distribution suggests that dopamine may control the GABAergic inhibitory processing of odor signals, possibly via different signal-transduction mechanisms. We have observed that GABAAreceptors in the rat olfactory bulb are differentially modulated by dopamine in a cell-specific manner. Dopamine reduced the currents through GABA-gated Cl-channels in the interneurons, presumably granule cells. This action was mediated via D1 receptors and involved phosphorylation of GABAAreceptors by protein kinase A. Enhancement of GABA responses via activation of D2 dopamine receptors and phosphorylation of GABAAreceptors by protein kinase C was observed in mitral/tufted cells. Decreasing or increasing the binding affinity for GABA appears to underlie the modulatory effects of dopamine via distinct receptor subtypes. This dual action of dopamine on inhibitory GABAAreceptor function in the rat olfactory bulb could be instrumental in odor detection and discrimination, olfactory learning, and ultimately odotopic memory formation.