I have recordings from stellate cells in the layer II entorhinal cortex. This synapse showed I-V relationship closely resemble that of GluR2 lacking AMPAR with strong rectification. The problem is, if it is GluR2 lacking AMPAR, we should not have strong rectification because we did not add any spermine in our pipette solution. Can anyone help me, is there any previous reports about polyamine independent inward rectification of GluR2 lacking AMPAR?
I wonder if this is not polyamine-independent. Could it be instead abundant endogenous spermine/spefmidine, which is at high levels in younger animals, because its role in development.
Thank you for your answer Victor. We used organotypic slice culture made from P6 rats. We cultured the slices for 14 days before recording. Furthermore, we were unable to detect NMDA response when we hold the potential at +40 mV. Can you place share your opinion in these matters?
I would think that it unusual for these cells not to have functional NMDA channels; but unfortunately, I am not fit to speculate on what might go wrong here, sorry. My best guess it is a technical issue with e.phys, but only a resident patcher could help to troubleshoot
Irwan, Polyamine sensitivity is variable among cell types. These cells could have abundant polyanimes that take a longer time to 'wash-out' when you patch. Ideally, you want to wash on Jurospider toxin or Phylanthotoxin to ascertain the GluA2 lacking AMPA receptors in these cells.
From the interneuron literature, it is well known that CP-AMPA receptors often lack NMDA receptors.
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