Intracellular spermine confers rectification on rat calcium‐permeable AMPA and kainate receptors.

摘要: 1. Whole-cell recordings were made from cerebellar granule cells cultured in high-K+ medium to induce expression of Ca(2+)-permeable AMPA receptors. Current-voltage (I-V) plots agonist-evoked responses showed varying degrees inward rectification, but became linear within 5-10 min. 2. Recombinant kainate receptors, composed GluR6(Q)/KA-2 subunits, exhibited rectifying whole-cell I-V that outside-out patches. 3. Loss rectification was prevented by including 100 microM spermine the pipette; degree then correlated with Ca2+ permeability. 4. Spermine also loss patches containing receptors (IC50, 1.7 microM). 5. We suggest spermine, or a similar cellular constituent, may act as cytoplasmic factor conferring on non-NMDA and 'washout' this underlies observed rectification.