Fig. 8.
Comparison of 5-HT-mediated vasoconstriction in the presence of K+ channel inhibitors in MCAs isolated from FHH and FHH.1BN rats. MCAs were mounted on glass micropipettes in a myograph, and intraluminal pressure was maintained at 80 mmHg. After 1 h of equilibration at 37°C, K+ channel blockers [4-AP, Kv channel blocker; Paxilline (Pax), BK channel blocker] combined with 100 nM 5-HT were applied to the chamber. A: diameter traces of 5-HT-mediated vasoconstriction in the presence or absence of 100 nM Pax. B: bar graph depicting the percent change in diameter (vasoconstriction) in the presence of 5-HT alone and in combination with BK channel blocker (+Pax, 100 nM) and/or Kv channel blocker (4-AP, 1 mM). *P < 0.05 between FHH and FHH.1BN rats; !significant difference in the corresponding values after K channel inhibition compared with 5-HT-mediated vasoconstriction alone in FHH rats. Error bars ± SE. Numbers in parentheses indicate the number of vessels studied.