Presynaptic kainate receptor activation preserves asynchronous GABA release despite the reduction in synchronous release from hippocampal cholecystokinin interneurons.
Inhibitory synaptic transmission in the hippocampus in mediated by a wide variety of different interneuron classes which are assumed to play different roles in network activity. Activation of presynaptic kainate receptors (KARs) has been shown to reduce inhibitory transmission but the interneuron class(es) at which they act is only recently beginning to emerge. Using paired recordings we show that KAR activation causes a decrease in presynaptic release from cholecystokinin (CCK)- but not parvalbumin-containing interneurons and that this decrease is observed when pyramidal cells, but not interneurons, are the postsynaptic target. We also show that although the synchronous release component is reduced, the barrage of asynchronous GABA release from CCK interneurons during sustained firing is unaffected by KAR activation. This indicates that presynaptic KARs preserve and act in concert with asynchronous release to switch CCK interneurons from a phasic inhibition mode to produce prolonged inhibition during periods of intense activity.
Daw
Michael I
MI
Program in Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Developmental Synaptic Plasticity Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA. michael.daw@ed.ac.uk
Pelkey
Kenneth A
KA
Chittajallu
Ramesh
R
McBain
Chris J
CJ
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002766:Cholecystokinin / Q000378:metabolism*; D006624:Hippocampus / Q000502:physiology*; D066298:In Vitro Techniques; D053444:Inhibitory Postsynaptic Potentials / Q000502:physiology; D007395:Interneurons / Q000502:physiology*; D007608:Kainic Acid / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009433:Neural Inhibition / Q000502:physiology; D010320:Parvalbumins / Q000378:metabolism; D017729:Presynaptic Terminals / Q000502:physiology*; D017966:Pyramidal Cells / Q000502:physiology; D043884:Receptor, Cannabinoid, CB1 / Q000378:metabolism; D018080:Receptors, GABA-B / Q000378:metabolism; D018092:Kainic Acid Receptors / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D002766:Cholecystokinin; D007608:Kainic Acid; D010320:Parvalbumins; D043884:Receptor, Cannabinoid, CB1; D018080:Receptors, GABA-B; D018092:Kainic Acid Receptors; D005680:gamma-Aminobutyric Acid