Q/R site editing controls kainate receptor inhibition by membrane fatty acids - PubMed (original) (raw)

Weak inhibition of Q/R heteromeric receptors. A, B, Current evoked by 10 μ

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kainate applications indicated by open bars, before and after exposure to 15 μ

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DHA, as indicated by the solid bar. C, Normalized currents as a function of holding potential for cells transfected with R6(R) (n = 8 cells), R6(R) plus R5(R) (n = 4 cells), R5(Q) (n = 4 cells), R6(R) plus KA2 (n = 5 cells), R5(R) plus KA2 (n = 6 cells), R6(R) plus R5(Q) (n = 8 cells), or R6(Q) plus R5(R) (n = 6 cells). D, Inhibition as a function of DHA concentration. Current evoked by 10 μ

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kainate (n = 3-9 cells per point) immediately after exposure to DHA is plotted as a fraction of the current before DHA. Smooth curves are the best fit of the following: I/I control = 0.1 + (0.9/(1 + ([DHA]/IC50)n̂)), where IC50 is the DHA concentration producing half-maximal inhibition, and n is the slope factor. R6(R) plus R5(R), IC50 = 2.6 μ

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, n = 1.02; R6(R) plus KA2, IC50 = 36.4 μ

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, n = 2.73; R5(R) plus KA2, IC50 = 51.5 μ

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, n = 2.24; R6(R) plus R5(Q), IC50 = 86.1 μ

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, n = 1.01; R6(Q) plus R5(R), IC50 = 192.3 μ

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, n = 0.74. Data for R6(R) and R5(Q) are replotted from Figure 1_C_. Data from cultured rat hippocampal neurons (hippocampus, dark gray circles) were adapted from Wilding et al. (1998).