Vasodilatory Effects of Diazepam on Human Umbilical and Mesenteric Arteries: An In Vitro Experimental Study
DOI:
https://doi.org/10.63356/stes.med.2025.008Keywords:
diazepam, vasoconstriction, vasorelaxation, human umbilical artery, human mesenteric artery, organ bathAbstract
Introduction: Benzodiazepines, primarily known for their central effects, are increasingly associated with direct effects on peripheral vascular tone. Although experimental studies on animal models
have demonstrated that diazepam can induce CNS-independent vasorelaxation, data regarding its effects on human blood vessels remain limited.
Aim: The purpose of this study was to examine the influence of diazepam on the tone of the human umbilical and mesenteric arteries.
Materials and Methods: The primary method for assessing vascular responses was the use of an organ bath system for isolated tissue experiments. Human umbilical arteries (HUA) were obtained from healthy women undergoing elective cesarean section, while human mesenteric arteries (HMA) were collected from patients undergoing elective intestinal surgery. Arterial segments 3–4 mm in length were prepared and mounted in the organ bath chambers. Viability was confirmed using potassium chloride at a concentration of 6x10-2 M. HUA were precontracted with serotonin (10-10–10-4 M) and HMA with phenylephrine (10-8–10-4,5 M). Diazepam was added cumulatively (10-8–10-4 M). Arterial contraction was expressed as a percentage of the maximal KCl-induced contraction, and relaxation as a percentage of the maximal precontraction.
Results: Serotonin induced a concentration-dependent vasoconstriction in HUA, which, at a concentration of 10-4 M, amounted to ~225% of the KCl-induced contraction. Phenylephrine induced a concentration-dependent vasoconstriction in HMA, which, at a concentration of 10-4,5 M, amounted to ~250% of the KCl-induced contraction. Diazepam produced concentration-dependent vasorelaxation in both artery types: ~96% in HUA and ~89% in HMA at 10-4 M.
Conclusion: These findings demonstrate that diazepam induces strong, concentration-dependent vasorelaxation in isolated, precontracted human umbilical and mesenteric arteries, confirming the existence of its peripheral effect.
