Multiple G-protein-coupled receptors mediate presynaptic inhibition at single excitatory synapses in the rat visual cortex.
Modulation of excitatory synaptic transmission by agonists for several neurotransmitter receptors was investigated at intrinsic cortical synapses derived from single presynaptic neurons. Excitatory postsynaptic currents (EPSCs) were recorded from layer 5 pyramidal neurons in the rat visual cortex in response to minimal stimulation within the same layer. 5-hydroxytryptamine, adenosine, baclofen, carbachol and DCG-IV all suppressed EPSCs with an increase in paired-pulse ratio. These agonists reduced the frequency of miniature EPSCs without significantly affecting their amplitude distribution. These results suggest that glutamatergic excitatory transmission in the neocortex is under the control of presynaptic inhibition mediated by multiple neuromodulator receptors co-expressed in single presynaptic terminals.
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Department of Pharmacology and Neurobiology, Graduate School of Medicine, Tokyo Medical & Dental University and CREST, JST (Japan Science and Technology Corporation), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. t-murakoshi.mphm@tmd.ac.jp
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Konishi
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Tanabe
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D000241:Adenosine / Q000494:pharmacology; D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology; D001418:Baclofen / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D018678:Cholinergic Agents / Q000494:pharmacology; D003521:Cyclopropanes / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D018755:GABA Agonists / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism*; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D009433:Neural Inhibition / Q000502:physiology*; D017966:Pyramidal Cells / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017661:Receptors, Presynaptic / Q000378:metabolism; D012701:Serotonin / Q000494:pharmacology; D014793:Visual Cortex / Q000166:cytology / Q000378:metabolism*
D000927:Anticonvulsants; D018678:Cholinergic Agents; D003521:Cyclopropanes; D018755:GABA Agonists; D011956:Receptors, Cell Surface; D017661:Receptors, Presynaptic; C082313:2-(2,3-dicarboxycyclopropyl)glycine; D012701:Serotonin; D002217:Carbachol; D019204:GTP-Binding Proteins; D001418:Baclofen; D000241:Adenosine; D005998:Glycine