Figure 4.

Neural agrin and electrical muscle stimulation affect AChR stability. SOL muscles were injected with Rh-BuTx 8 days after denervation and injection of solutions of nAgrin cDNA that resulted in low, medium, and high amounts of recombinant nAgrin in the muscles as indicated. Relative fluorescence at nAgrin-induced AChR aggregates (ordinate, see Materials and Methods) declined at fast, intermediate, and slow rates in muscles expressing low, medium, or high amounts of recombinant protein (■). Electrical muscle stimulation starting on the day of Rh-BuTx injection decreased the degradation rate at AChR aggregates induced in muscles expressing low or medium but not high amounts of recombinant nAgrin (○). For each time point, 13–64 measurements were done in at least three different animals.