PT  - JOURNAL ARTICLE
AU  - Frerking, Matthew
AU  - Ohliger-Frerking, Patricia
TI  - AMPA Receptors and Kainate Receptors Encode Different Features of Afferent Activity
AID  - 10.1523/JNEUROSCI.22-17-07434.2002
DP  - 2002 Sep 01
TA  - The Journal of Neuroscience
PG  - 7434--7443
VI  - 22
IP  - 17
4099  - http://www.jneurosci.org/content/22/17/7434.short
4100  - http://www.jneurosci.org/content/22/17/7434.full
SO  - J. Neurosci.2002 Sep 01; 22
AB  - Postsynaptic kainate receptors (KARs) have been found in the CNS along with AMPA receptors (AMPARs), but because KAR-mediated EPSCs are much smaller and slower than AMPAR-mediated EPSCs, it remains unclear whether these postsynaptic KARs are functionally significant. In this study we measured KAR- and AMPAR-mediated EPSPs in hippocampal interneurons, and then we used these EPSPs in a model to examine the effects of afferent firing on each receptor. In this model the KARs generated a large tonic depolarization when activated by a small population of afferent fibers firing asynchronously at physiologically relevant firing rates (1–5 Hz). At 3–5 Hz this tonic depolarization exceeded the peak depolarization mediated by AMPARs in response to the same afferent activity. We also found that, unlike AMPARs, KARs did not generate large oscillations in membrane potential during theta rhythms. When simulated EPSCs were injected into interneurons to mimic afferents firing at 5 Hz, we found that currents simulating KARs elicited more spiking than currents simulating AMPARs. We also found that simulated AMPARs, but not KARs, could transmit presynaptic theta rhythms into postsynaptic spiking at the theta rhythm. Our results suggest that synaptically activated KARs have a strong influence on membrane potential and that AMPARs and KARs differ in their ability to encode temporal information.