Citral relaxes umbilical vessels of normotensive and preeclamptic parturients.

INTRODUCTION: Citral is a low-toxicity monoterpene that has a vasodilator effect on various smooth muscles, and The present study aimed to evaluate its vasorelaxant effect on umbilical vessels of normotensive parturients (NTP) and with preeclampsia parturients (PEP). METHOD: Segments of human umbilical artery (HUA) and vein (HUV) of NTP or PEP were mounted in a bath to record the force of contraction, under tension of 3.0 gf and contracted with the contracting agents: K+ (60 mM), 5 -HT (10 µM) and Ba2+ (1-30 mM). Next, the effect of citral (1-3000 µM) on these contractions and on basal tone was evaluated. RESULTS: In HUA and HUV, citral (1-1000 µM), in NTP condition, inhibited contractions evoked by K+ (IC50 of 413.5 and 271.3, respectively) and by 5-HT (IC50 of 164.8 and 574.3). In the PEP condition, in HUA and HUV, citral also inhibited the contractions evoked by K+ (IC50 of 363.3 and 218.3, respectively) and 5-HT (IC50 of 432.1 and 520.4). At a concentration of 1000 µM, citral completely or almost completely (>90 %) inhibited all contractions. At a concentration of 100-1000 µM, citral, in general, was already able to reduce the contraction induced by 1-3 mM Ba2+ in both AUH and VUH, under NTP and PEP conditions. DISCUSSION: Citral has been shown to be an effective HUA and HUV vasodilator in NTP and PEP. As its toxicity is low, it suggests that this substance can be considered a potential therapeutic agent.

Perillyl Alcohol Promotes Relaxation in Human Umbilical Artery.

BACKGROUND: Perillyl alcohol (POH) is a monoterpenoid found in plant essential oils and has been shown to relax murine vessels, but its effect on human vessels remains poorly studied. OBJECTIVE: The study aimed to characterize the effect of POH on human umbilical arteries (HUA). METHODS: Rings of HUA were obtained from uncomplicated patients and suspended in an organ bath for isometric recording. The vasorelaxant effect of POH in HUA was evaluated on basal tone and electromechanical or pharmacomechanical contractions, and possible mechanisms of action were also investigated. RESULTS: POH (1-1000 µM) altered the basal tone of HUA and completely relaxed HUA rings precontracted with KCl (60 mM) or 5-HT (10 µM), obtaining greater potency in the pharmacomechanical pathway (EC50 110.1 µM), suggesting a complex interference in the mobilization of extra- and intracellular Ca2+. POH (1000 µM) inhibited contractions induced by BaCl2 (0.1-30 mM) in a similar way to nifedipine (10 µM), indicating a possible blockade of L-type VOCC. In the presence of potassium channel blockers, tetraethylammonium (1 mM), 4-aminopyridine (1 mM), or glibenclamide (10 µM), an increase in the EC50 value of the POH was observed, suggesting a modulation of the activity of BKCa, KV, and KATP channels. CONCLUSION: The data from this study suggest that POH modulates Ca2+ and K+ ion channels to induce a relaxant response in HUA.