Fig. 3.

LN induces AChR aggregation in C2 but not S27 cells. Cultures were treated for 18 hr with 0, 12, 24, 60, or 120 nm LN, labeled with rhodamine-conjugated α-bungarotoxin, and the number of AChR aggregates per myotube segment was quantified. Data points represent the mean ± SEM of four experiments. For each experiment, 10 fields taken at random from each of four coverslips were quantified. LN induces the first significant increase in the number of AChR aggregates in C2 cells (open circles) at a concentration of 24 nm. The response saturates at 60 nm with a twofold increase in the number of AChR aggregates over control. An asterisk indicates numbers of LN-induced AChR clusters that are statistically significant from control as assessed by ANOVA and Fisher’s test (p < 0.05). In contrast, no AChR aggregates were present in S27 cultures (filled circles) at any concentration of LN tested.