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The Role of the Endothelium in Altering Vascular Reactivity Following Acute Hyperbaric Oxygen Treatment
Author(s) -
Janardan Veena,
Bontekoe Jack,
Ophoff Brad,
Horr Kyle,
Sylvester Francis
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.lb594
Subject(s) - phenylephrine , vasodilation , sodium nitroprusside , chemistry , dilator , acetylcholine , endothelium , anesthesia , medicine , nitric oxide , blood pressure
Acute hyperbaric oxygen treatment (HBOT) alters vascular reactivity, yet the underlying mechanism requires further clarification. As Furchgott and Zawadzki previously demonstrated the obligatory role of the endothelium in regulating blood vessel tone, our lab seeks to determine if the simple squamous epithelium of the tunica intima mediates the observed changes in vascular reactivity following HBOT. Intact or chemically denuded porcine, mesenteric arterial rings were exposed to one of three treatments: 100% oxygen at 1.75 atm, room air at 1.75 atm, and room air at 1.00 atm. Additionally, a separate series of experiments utilized a Clark type electrode to measure the oxygen concentrations observed in the hyperbaric chamber. These recordings demonstrated significant differences among the three treatment groups. Following two hours of exposure to hyperbaric treatment, vessels were mounted in isolated organ baths and coupled to force transducers so that changes in arterial force were recorded in response to multiple agonists. The vasoconstrictors, potassium chloride (6×10 −2 M) and phenylephrine (10 −7 ‐3×10 −6 M), were used to record increases in tension. The vasodilators, acetylcholine (10 −7 ‐ 10 −4 M) and sodium nitroprusside (10 −7 ‐ 10 −4 M), were used to record decreases in tension. Lack of a dilator response to acetylcholine, an endothelial‐dependent vasodilator, was used as validation for denudation. Potassium chloride and phenylephrine induced significant increases in tension in all treatments. Nitroprusside induced significant decreases in tension in all treatments. Comparison of the intact arteries to the denuded arteries following HBOT indicated that the endothelium did not account for the changes in vascular reactivity. Further investigation of the acute effects of HBOT on vascular reactivity is needed to better understand the potential benefits of hyperbaric oxygen therapy for treating cardiovascular disease.