Inhibitory effects of the anesthetics propofol and sevoflurane on spontaneous lymphatic vessel activity in rats.

Background: The effects of propofol and sevoflurane on lymphatic vessel activity are unknown. This study aimed to clarify the effects of these anesthetics on lymphatic vessel activity in rats by the use of a technique for mechanical removal of the endothelium. Methods: The authors first examined the effects of propofol (8 mg/kg) and sevoflurane (2.0%) on in vivo lymphatic flow by injection of dye into the femoral regions of rats. In the in vitro study, the ends of the vessel segments of rat thoracic duct were connected to a syringe and stopcock, respectively. Spontaneous changes in diameter of each segment were monitored, and the extraluminal side of each segment was exposed to propofol (1 x 10 -6 ∼ 3 × 10 -5 M) or sevoflurane (0.5∼2.0%). Endothelial function was eliminated by perfusion of air into the lumen. Results: In the dye uptake study, 80% of iliac lymphatic nodes were positively stained in a control group, whereas only 10% and 20% were positively stained in propofol and sevoflurane groups, respectively. In the in vitro study, both of the anesthetics significantly decreased the amplitude of spontaneous activity of lymphatic vessels with or without endothelial function. Sevoflurane inhibited the frequency of lymphatic vessel activity but propofol had no effect on it. When the endothelial function was eliminated, both anesthetics decreased the frequency of spontaneous activity of lymphatic vessels. Conclusions: Propofol and sevoflurane seem to have some different effects on endothelial function, which regulates the pacemaking of spontaneous contraction of lymphatic vessels.