Metabotropic-mediated kainate receptor regulation of IsAHP and excitability in pyramidal cells.
Kainate receptors (KARs) on CA1 pyramidal cells make no detectable contribution to EPSCs. We report that these receptors have a metabotropic function, as shown previously for CA1 interneurons. Brief kainate exposure caused long-lasting inhibition of a postspike potassium current (I(sAHP)) in CA1 pyramidal cells. The pharmacological profile was independent of AMPA receptors or the GluR5 subunit, indicating a possible role for the GluR6 subunit. KAR inhibition of I(sAHP) did not require ionotropic action or network activity, but was blocked by the inhibitor of pertussis toxin-sensitive G proteins, N-ethylmaleimide (NEM), or the PKC inhibitor calphostin C. These data suggest how KARs, putatively containing GluR6, directly increase excitability of CA1 pyramidal cells and help explain the propensity for seizure activity following KAR activation.
Melyan
Zare
Z
Centre for Neuroscience, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, United Kingdom.
Wheal
Howard V
HV
Lancaster
Barrie
B
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D007608:Kainic Acid / Q000494:pharmacology; D024661:Potassium Channels, Inwardly Rectifying / Q000037:antagonists & inhibitors / Q000502:physiology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D017966:Pyramidal Cells / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D018092:Kainic Acid Receptors / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*; D000097806:GluK2 Kainate Receptor
D018690:Excitatory Amino Acid Agonists; D007608:Kainic Acid; D024661:Potassium Channels, Inwardly Rectifying; D011493:Protein Kinase C; D018092:Kainic Acid Receptors; D018094:Receptors, Metabotropic Glutamate; D000097806:GluK2 Kainate Receptor