Figure 2. LNNA-induced tone is gender-dependent but K⁺ and ET-1 induced tone is gender-independent.

Vascular diameter was monitored at intramural pressures of 20, 40, 60 and 80 cmH₂O while vessel segments were superfused with PSS solution to which 10 µM LNNA was added, with 150 mM K⁺ solution to which 10 µM LNNA and 10 nM ET-1 were added, and with Ca²⁺ free solution to which 100 µM papaverine was added (0 Ca+Pap). A) Summary of diameter measurements performed in male SMAs. The superfusion protocol is indicated by bars located above the data trace. Intramural pressures are indicated by bars located below the data trace. The data trace represents the average of 10 vessel segments. Data were acquired at 1 s intervals, however, for clarity, error bars (sem) are plotted only every 50 s. B) Summary of the calculated tone in female SMAs. C) Summary of the calculated tone in male SMAs. The legend provided in C applies to B and C. Numbers next to symbols in B and C represent the number of vessel segments. Stars indicate a significant change in tone at a given pressure compared to the prior condition.