Development of an experimental apparatus for investigating lymphatic pumping activity of murine mesentery in vivo

The present study has been attempted to establish a modified intravital mic roscope system for investigating murine lymphatic pumping activity in vivo and evaluate whether or not there is rhythmic pumping activity of murine me senteric lymphatic vessels in vivo. We designed and constructed a custom or gan chamber with a semicircular channel (8 mm in radius, 5 mm in width, 3 m m in depth), being suitable for the superfusing of murine mesentery in vivo . A marked lymphatic pumping activity was observed in the mesenteries of DD Y mice. The maximal and minimal diameter and frequency in the pumping activ ity were 60.9+/-1.0 mu m, 53.7+/- 1.8 mu m and 12.8 min(-1) (n=5), respecti vely. Both NE (norepinephrine, 10(-)8-10(-6) M) and TEA (tetraethylammonium , 1-10 mM) caused dose-dependent constriction of the mesenteric lymphatic v essels in the mice. These findings suggest that a modified intravital micro scope system with a specially designed and constructed edge-monitoring devi ce enables us to investigate in vivo lymphatic circulation in murine mesent eries.