Figure 7. There are no additive effects of genetic IP₃ signaling inhibition and pharmacological RyR inhibition.

(A) GluRIII knockdown diminishes quantal size for all experimental conditions. (B) When challenged with GluRIII knockdown, EPSP amplitudes are maintained for the GAL4 driver control background but impaired for all other experimental backgrounds. The dual manipulation of 10 µM Dantrolene +UAS-IP₃-sponge is indistinguishable from the single manipulations alone. (C) By quantal content, sustained PHP expression is abolished with chronic IP₃ sequestration, acute 10 µM Dantrolene application, or both. (D) Representative electrophysiological traces for the conditions in (A–C). (E) Acute incubation 20 μM PhTox diminishes quantal size for all conditions shown. (F) EPSP amplitudes remain near genetic control levels for all conditions with PhTox application. There is a slight diminishment for the condition in which UAS-IP₃-sponge is expressed and PhTox application is performed only after nerve dissection. (G) Full, rapid PHP induction or partial PHP induction by PhTox is present for all conditions shown. (H) Representative electrophysiological traces for the conditions in (E–G). Violin plots used as in Figure 1. Statistical comparisons for (A–C) and for wild type vs. wild type +PhTox are by Student’s T-Test vs. unchallenged controls. Statistical comparisons across three data sets are by one-way ANOVA followed by Bonferroni post-hoc test across genotypes shown. *p<0.05, **p<0.01, ***p<0.001. Scale bars for all traces are y = 10 mV (1 mV), x = 20 ms (500 ms) for EPSPs (mEPSPs).