Fig. 9.

Contractile synchronization is endothelium dependent. LECs were removed from the lumen of the vessel. A: while the vessel showed strong intrinsic contractions before dynamic flow is imposed, as is evidenced by the contractile amplitude, the vessel no longer displays strong intrinsic contractions phase-locked with the dynamic flow waveform when the endothelium has been physically disturbed. B: when the endothelium is mechanically damaged, the vessel has a reduced and highly variable contraction frequency under no flow. When dynamic shear is imposed on the vessel, the vessel still contracts at a frequency similar to the imposed waveform. **P < 0.01; ***P < 0.001.