Human umbilical artery (HUA) preparations are of particular importance for in
vitro studies on isolated blood vessels because their sampling is not risky for the
patient, and they can provide the closest possible impression of changes related to
the uteroplacental circulation during pre-eclampsia. Using organ bath techniques,
useful experimental protocols are provided for measuring some pathophysiological
phenomena in the vascular responses of HUAs. Several vasoconstrictors (serotonin,
prostaglandin F and phenylephrine) and vasodilators (acetylcholine and minoxidil)
were seleted for determination of their vasoactivity in HUAs. The role of Ltype
voltage-operated calcium channels and different types of potassium channels
(KATP, BKCa and KV) were assessed, as was the impact of homocysteine. Serotonin
was confirmed to be the most potent vasoconstrictor, while acetylcholine and
phenylephrine caused variability in the relaxation and contraction response of HUA,
respectively. The observed increase in serotonin-induced contraction and a decrease
in minoxidil-induced relaxation in the presence of homocysteine suggested its
procontractile effect onHUApreparations.Using selective blockers, it was determined
that KATP and KV channels participate in the minoxidil-induced relaxation, while Ltype
voltage-dependent Ca2+ channels play an important role in the serotonin-induced
contraction. The presented protocols reveal some of the methodological challenges
related to HUA preparations and indicate potential outcomes in interpreting the
vascular effects of the investigated substances, both in physiological conditions and in
the homocysteine-induced pre-eclampsia model.
