Climbing fiber-triggered metabotropic slow potentials enhance dendritic calcium transients and simple spike firing in cerebellar Purkinje cells.
Cerebellar Purkinje cells (PCs) receive synaptic input from numerous parallel fibers (PFs) and from a single climbing fiber (CF). At both types of synapses, fast synaptic transmission is mediated by AMPA receptors, while at PF synapses burst activity can additionally recruit metabotropic glutamate receptors (mGluRs) that mediate a slow depolarizing potential. Here, we show that mGluR-activated slow potentials can be evoked throughout the dendrite by CF-evoked complex spike firing in the presence of an mGluR agonist. The CF-triggered mGluR potential was not only blocked by an mGluR antagonist but also when the CF-induced Ca(2+) transient was blocked by an AMPA receptor antagonist, suggesting the possibility that the slow potential can be activated by the simultaneous occurrence of agonist binding at mGluRs and a CF-evoked Ca(2+) transient. In turn, these CF-triggered slow mGluR potentials enhance the complex spike-associated calcium signals throughout the dendrite. Moreover, they provide a mechanism by which CFs can modulate the simple spike frequency of PCs.
Yuan
Qi
Q
Laboratory for Neuronal Circuit Dynamics, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
Qiu
De-Lai
DL
Weber
John T
JT
Hansel
Christian
C
Knöpfel
Thomas
T
D000814:Aniline Compounds / Q000378:metabolism; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D003712:Dendrites / Q000378:metabolism*; D018691:Excitatory Amino Acid Antagonists / Q000378:metabolism; D005452:Fluoresceins / Q000378:metabolism; D008564:Membrane Potentials / Q000502:physiology*; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives / Q000378:metabolism; D051379:Mice; D018408:Patch-Clamp Techniques; D011689:Purkinje Cells / Q000166:cytology / Q000502:physiology; D011810:Quinoxalines / Q000378:metabolism; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology*
D000814:Aniline Compounds; D018691:Excitatory Amino Acid Antagonists; D005452:Fluoresceins; C503942:Oregon green 488 BAPTA-1; D011810:Quinoxalines; D018091:Receptors, AMPA; D018094:Receptors, Metabotropic Glutamate; C120673:benzyloxyaspartate; C062865:2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline; D001224:Aspartic Acid; D008734:Methoxyhydroxyphenylglycol; D002118:Calcium; C010117:3,4-dihydroxyphenylglycol