Fig. 6.
The ryanodine receptor (RyR)1/RyR3 inhibitor dantrolene does not inhibit rat mesenteric collecting lymphatic contractions or the increased CF and decreased EDD/Max elicited by substance P (SP). Representative trace of diameter over time of an isolated rat mesenteric collecting lymphatic vessel before and after the addition of 10−5 M dantrolene, which remained in the bath (A). Continuation of the same trace, showing the addition of 10−8 M SP in the presence of dantrolene (B). The boxes beneath the traces in A and B indicate 2-min time periods during which the quantitative data used for comparisons in C–H were collected. Comparisons between baseline (BL), after addition of dantrolene, and after addition of SP in the presence of dantrolene were performed for CF (C), EDD/MaxD (D), ESD/MaxD (E), AMP/MaxD (F), EF (G), and FPF (H). P values are shown for comparisons that were found to be significantly different (P < 0.05) using Tukey’s multiple comparison test after an initial one-way repeated measures ANOVA. N = 6 isolated lymphatics studied from 6 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.