title: Dendritic glutamate release produces autocrine activation of mGluR1 in cerebellar Purkinje cells.
abstract: In recent years, it has become clear that, in addition to conventional anterograde transmission, signaling in neural circuits can occur in a retrograde manner. This suggests the additional possibility that postsynaptic release of neurotransmitter might be able to act in an autocrine fashion. Here, we show that brief depolarization of a cerebellar Purkinje cell triggers a slow inward current. This depolarization-induced slow current (DISC) is attenuated by antagonists of mGluR1 or TRP channels. DISC is eliminated by a mixture of voltage-sensitive Ca2+ channel blockers and is mimicked by a brief climbing fiber burst. DISC is attenuated by an inhibitor of vesicular glutamate transporters or of vesicular fusion. These data suggest that Ca2+-dependent postsynaptic fusion of glutamate-loaded vesicles evokes a slow inward current produced by activation of postsynaptic mGluR1, thereby constituting a useful form of feedback regulation.
authors.affiliation: Department of Neuroscience, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, 916 Hunterian Building, Baltimore, MD 21205, USA.
authors.forename: Jung Hoon
authors.initials: JH
authors.lastname: Shin
authors.forename: Yu Shin
authors.initials: YS
authors.lastname: Kim
authors.forename: David J
authors.initials: DJ
authors.lastname: Linden
mesh_terms: D000818:Animals; D019898:Autocrine Communication; D002118:Calcium / Q000378:metabolism; D002531:Cerebellum / Q000378:metabolism*; D003712:Dendrites / Q000378:metabolism*; D004594:Electrophysiology; D019706:Excitatory Postsynaptic Potentials; D018698:Glutamic Acid / Q000378:metabolism*; D018613:Microscopy, Confocal; D008954:Models, Biological; D011689:Purkinje Cells / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction
chemical_list: D018094:Receptors, Metabotropic Glutamate; C104077:metabotropic glutamate receptor type 1; D018698:Glutamic Acid; D002118:Calcium