Figure 8. The expression of synaptic homeostasis is suppressed by mutations in the Ca_V2.1 alpha-1 subunit.

A) Quantification of average mepsp amplitude (filled bars) and quantal content (open bars). Values are normalized to wild-type control (dotted line). GluRIIA mutants have decreased mepsp amplitudes and a homeostatic increase in quantal content (p<0.001 for both). B) Values as in (A) are normalized to those observed in the cac^S/+ heterozygous condition. A homeostatic increase in quantal content is observed in the cac^S/+; GluRIIA animals (p<0.01). However, the magnitude of the increase in quantal content is significantly less than that observed in GluRIIA mutants shown in (A) (p<0.01). C) Quantification as in (A) for control and cac^S;GluRIIA double mutants. Data are normalized to values observed in cac^S alone. A homeostatic increase in quantal content is suppressed in the cac^S;GluRIIA double mutant compared to cac^S alone (p>0.2). D) Quantification as in (A) for control and GluRIIA mutants recorded in 1.5mM extracellular calcium. GluRIIA mutants show a compensatory increase in quantal content at 1.5mM extracellular calcium compared to wild type (p<0.01). Quantal contents were corrected for non-linear summation prior to normalization. E) The homeostatic increase in quantal content is suppressed in the cac^S;GluRIIA double mutant compared to cac^S mutants alone, recorded in 1.5mM extracellular calcium (p>0.5).