Fig. 1.
Acute response of isolated rat mesenteric collecting lymphatic vessels to substance P (SP). Representative trace of diameter over time of an isolated rat collecting mesenteric lymphatic vessel before and after addition of 10−8 M SP, indicated by the arrow (A). The inflow and outflow pressures were held at 2 cm H2O throughout the experiment. The boxes above the x-axis indicate the 2-min time periods used for measurements of lymphatic parameters that are provided in B–G. Comparisons between baseline and after addition of SP are shown for CF (B), EDD/MaxD (C), ESD/MaxD (D), AMP/MaxD (E), EF (F), and FPF (G). P values were obtained from paired t-tests and are shown for each comparison considered significant (P < 0.05). N = 25 collecting lymphatic vessels isolated from 25 different rats. CF, contraction frequency; EDD, end-diastolic diameter; EF, ejection fraction; ESD, end-systolic diameter; FPF, fractional pump flow; MaxD, maximal passive diameter; NS, not significant.