AMPA receptor flip and flop RNA splicing in hippocampal principal cells

Development of AMPA receptor flip and flop RNA splicing in hippocampal principal cells 

The flip and flop mRNA splice variants appear at different times during development. The flop versions are expressed at low levels prior to postnatal day 8 their characteristic high expression in CAl pyramidal cells becomes apparent only during the second postnatal week (Fig. 16) (Monyer et al., 1991). In contrast, flip RNA levels are already substantial in pyramidal cells from birth (Monyer et al., 1991). As the CAl pyramidal cells mature, the recruitment of the flop cassette into the AMPA receptors may cause these receptors to ipactivate faster (Mosbacher et al., 1994). 

AMPA receptor subunit mRNA in hippocampal interneurons 

Numerous intemeurons in the hippocampus are labelled with GluR-A and -D probes (Figs. 15 and 17) (Sommer et al., 1990 Monyer et al., 1991 Catania et al., 1995, 1998), and there are some cells (especially in the stratum oriens) which are strong GluR-C expressors (Monyer et al., 1991 Catania et al., 1998). Many putative intemeurons in the oriens, pyramidal and radiatum layers in both the CAl and CA3 sectors strongly express subunits as flop, but not flip, variants (Fig. 15) (Monyer et al., 1991). 

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