Figure 4. Effects of RGD on Mn²⁺-treated junctions.

In muscles treated with zero-Ca²⁺ Ringer and 0.5 mm Mn²⁺, the resting mEPP frequency was close to normal (single traces and summary bar graph a), and addition of 25 mm sucrose caused an approximately 4-fold increase in frequency (b). Preparations treated similarly but in the presence of 0.2 mm RGD showed a slightly depressed resting mEPP frequency (c) and a severely reduced enhancement of release by 25 mm sucrose (d).