Different sensitivities of vasoconstrictor responses to serotonin and KCl of isolated and perfused dog mesenteric arteries with and without endothelia.

The stainless steel cannula inserting method was used to investigate the effects of serotonin on isolated and perfused dog mesenteric arteries with and without intraluminal saponin treatment. By intraluminal administration, serotonin and potassium chloride caused dose-related vasoconstrictions. After intraluminal treatment with 3 mg of saponin, the potassium chloride-induced vasoconstrictor response was significantly enhanced, whereas the serotonin-induced one was not potentiated but rather reduced slightly.