Presynaptic long-term depression at a central glutamatergic synapse: a role for CaMKII.
CaMKII is a calcium-activated kinase that is abundant in neurons and has been strongly implicated in memory and learning. Here we show that low-frequency stimulation of glutamatergic afferents in hippocampal slices from juvenile domestic chicks results in long-term depression of synaptic transmission. This reduction does not require activation of NMDA or metabotropic glutamate receptors and does not require a rise in postsynaptic calcium. However, buffering presynaptic calcium prevents the reduction of the excitatory postsynaptic potential or current that is induced by low-frequency stimulation. In addition, application of the calmodulin antagonist calmidazolium, or the specific CaMKII antagonist KN-93, completely blocks long-term depression. These findings demonstrate a newly discovered form of long-term synaptic depression in the avian hippocampus.
Margrie
T W
TW
Neuroscience Group, Faculty of Medicine and Health Sciences, University of Newcastle, Callaghan NSW, Australia.
Rostas
J A
JA
Sah
P
P
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology; D001921:Brain / Q000502:physiology*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000502:physiology*; D002645:Chickens; D004558:Electric Stimulation; D005973:Glutamine / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000502:physiology*; D017729:Presynaptic Terminals / Q000502:physiology*; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology
D005973:Glutamine; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases