Long-term depression at parallel fiber to Golgi cell synapses.
Golgi cells (GoCs) are the primary inhibitory interneurons of the granular layer of the cerebellum. Their inhibition of granule cells is central to operate the relay of excitatory inputs to the cerebellar cortex. Parallel fibers (PFs) establish synapses to the GoCs in the molecular layer; these synapses contain AMPA, N-methyl-D-aspartate (NMDA), and mostly group II metabotropic glutamate receptors. Long-term changes in the efficacy of synaptic transmission at the PF-GoC synapse have not been described previously. We used whole cell patch-clamp recordings of GoCs in acute rat cerebellar slices to study synaptic plasticity. We report that high-frequency burst stimulation of PFs, using a current-clamp or voltage-clamp induction protocol, gave rise to long-term depression (LTD) at the PF-GoC synapse. This form of LTD was not associated with persistent changes of paired-pulse ratio, suggesting a postsynaptic origin. Furthermore, LTD induction was not dependent on activation of NMDA receptors. PF-GoC LTD does require activation of specifically group II metabotropic glutamate receptors and of protein kinase A.
Robberechts
Quinten
Q
Theoretical Neurobiology, Dept. of Biomedical Sciences, Campus Drie Eiken T5.37, Univ. of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium. quinten@tnb.ua.ac.be
Wijnants
Mike
M
Giugliano
Michele
M
De Schutter
Erik
E
D000818:Animals; D002525:Cerebellar Cortex / Q000166:cytology / Q000502:physiology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D004558:Electric Stimulation; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D018698:Glutamic Acid / Q000502:physiology; D007395:Interneurons / Q000502:physiology*; D036881:Long-Term Synaptic Depression / Q000502:physiology*; D009412:Nerve Fibers / Q000502:physiology*; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D018094:Receptors, Metabotropic Glutamate / Q000187:drug effects / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects; D013569:Synapses / Q000502:physiology
D018691:Excitatory Amino Acid Antagonists; D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C108822:metabotropic glutamate receptor 2; D018698:Glutamic Acid; D017868:Cyclic AMP-Dependent Protein Kinases