Fig. 4. Protein synthesis is not required for SSC frequency facilitation induced by RA. The culture was pretreated with 30 µM anisomycin (A) or 30 µM cycloheximide (B) for more than 45 minutes and the effect of RA on SSC frequency was then evaluated. Scale bars, 500 pA, 20 seconds. (C) Summary of data for the SSC frequency (±s.e.m.) at 10-15 minutes after RA application under various drug pretreatment, normalized by mean control values from the same synapse before the addition of RA.