Figure 5

Suction from contracting lymphatic vessels is transmitted upstream to both contracting and non-contracting vessels. (A) Two lymphatic vessels were connected using a coupling cannula. Upstream vessel: mouse iliac efferent lymphatic (passive: non-contracting) (orange), downstream vessel: rat mesenteric lymphatic (active: contracting). Pressure (p ₁) was measured downstream of V1 in the passive vessel (N = 1). (B) Top: trace of p ₁ (orange). Bottom: D obtained at diameter tracking site A (orange) and B (black). Effect of R _capillary upstream (magenta). (C) Pressure and flow predictions from mathematical modelling. Left: pressure between two valves in the passive vessel (orange, solid), downstream of the second valve in the passive vessel (orange, dotted), pressure in the first lymphangion in the active vessel (black). Right: flow waveform in the passive vessel (orange), and through the first valve in the active vessel (black). Pressure drop from suction opened the valve in the passive segment and allowed lymphatic filling. (D) Two contracting lymphatic vessels from rat mesentery were connected (both active). Pressure (p ₁) was measured downstream of V1 in vessel 1. (E) Top: trace of p ₁ in vessel 1. Bottom: D obtained at diameter tracking site A (orange) and B (black). The pressure trace showed two dips in pressure associated with suction during expansion of the two vessels (N = 1). (F) Pressure and flow predictions from mathematical modelling. Left: pressure between two valves in vessel 1 (orange, solid), downstream of the second valve in vessel 1 (orange, dotted), pressure in the first lymphangion in vessel 2 (black). Right: flow waveform through the first valve in vessel 1 (orange), and through the first valve in vessel 2 (black).