Fig. 3.

Influence of vessel denudation and inhibition of ET-1 biosynthesis on myogenic tone in PCAs from young and aged Fischer 344 rats. Endogenous ET-1 biosynthesis was inhibited using phosphoramidon (PPA; 3 μM) to inhibit endogenous endothelin-converting enzyme-1 (ECE-1). a Myogenic tone in the PCAs of young rats before (n = 10) and after (n = 5) denudation. b Myogenic tone in the PCAs of aged rats before (n = 9) and after (n = 3) denudation. c Myogenic tone in the PCAs of young rats before (n = 10) and after (n = 4) treatment with PPA. d Myogenic tone in the denuded PCAs of young rats before (n = 5) and after (n = 4) treatment with PPA. e Myogenic tone in the PCAs of aged rats before (n = 9) and after (n = 5) treatment with PPA. * P < 0.05 vs. treatment with PPA and/or denudation at each pressure point. Significance was determined using repeated unpaired t tests with Holm-Sidak correction for multiple comparisons at each pressure point