Blebbistatin is a drug that specifically inhibits the assembly of myosin in the cytoskeleton. What effect would you expect blebbistatin to have on intracellular vesicles?
The formation of vesicles would cease. The movement of vesicles within the cell would cease. The vesicle membranes would fail and release their contents into the cytoplasm. The vesicles would be unable to fuse with the plasma membrane.
I don't readily see how Blebbistatin would effect intracellular vesicles; I believe this ignorance comes from not knowing what myosin is and how it interacts in the cytoskeleton.