Climbing fiber activation of metabotropic glutamate receptors on cerebellar purkinje neurons.
In the cerebellum, metabotropic glutamate receptors (mGluRs) are required for distinct forms of synaptic plasticity expressed at parallel fiber (PF) and climbing fiber (CF) synapses. At PF synapses, mGluR activation generates a slow synaptic current and triggers intracellular calcium release; at CF synapses, mGluR activation has not been observed. This has led some investigators to propose that mGluR-dependent changes in CF synaptic strength are induced heterosynaptically. Here we describe an mGluR-mediated response to CF stimulation consisting of two parallel signaling pathways: one leading to a slow synaptic conductance and the other leading to internal calcium release. This additional target for glutamate broadens the signaling capabilities of CF synapses and raises the possibility that changes in CF strength are homosynaptically triggered.
Dzubay
Jeffrey A
JA
Department of Neurobiology and The Brain Research Institute, School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
Otis
Thomas S
TS
D000375:Aging / Q000502:physiology; D027322:Amino Acid Transport System X-AG / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D004558:Electric Stimulation; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D018698:Glutamic Acid / Q000378:metabolism; D009434:Neural Pathways / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D009847:Olivary Nucleus / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism*; D011689:Purkinje Cells / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D018091:Receptors, AMPA / Q000187:drug effects / Q000378:metabolism; D017470:Receptors, Glutamate / Q000187:drug effects / Q000378:metabolism*; D018094:Receptors, Metabotropic Glutamate / Q000187:drug effects / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
D027322:Amino Acid Transport System X-AG; D018691:Excitatory Amino Acid Antagonists; D018091:Receptors, AMPA; D017470:Receptors, Glutamate; D018094:Receptors, Metabotropic Glutamate; D018698:Glutamic Acid; D002118:Calcium