Previously we reported modulation of endothelial prostacyclin and interleukin-8 production, cyclooxygenase-2 expression and vasorelaxation by oleoyl- lysophosphatidylcholine (LPC 18:1). In the present study, we examined the impact of this LPC on nitric oxide (NO) bioavailability in vascular endothelial EA.hy926 cells. Basal NO formation in these cells was decreased by LPC 18:1. This was accompanied with a partial disruption of the active endothelial nitric oxide synthase (eNOS)- dimer, leading to eNOS uncoupling and increased formation of reactive oxygen species (ROS). The LPC 18:1-induced ROS formation was attenuated by the superoxide scavenger Tiron, as well as by the pharmacological inhibitors of eNOS, NADPH oxidases, flavin-containing enzymes and superoxide dismutase (SOD). Intracellular ROS-formation was most prominent in mitochondria, less pronounced in cytosol and undetectable in endoplasmic reticulum. Importantly, Tiron completely prevented the LPC 18:1-induced decrease in NO bioavailability in EA.hy926 cells. The importance of the discovered findings for more in vivo like situations was analyzed by organ bath experiments in mouse aortic rings. LPC 18:1 attenuated the acetylcholine-induced, endothelium dependent vasorelaxation and massively decreased NO bioavailability. We conclude that LPC 18:1 induces eNOS uncoupling and unspecific superoxide production. This results in NO scavenging by ROS, a limited endothelial NO bioavailability and impaired vascular function.
Objective:
Parachuting and bungee jumping result in heavy mental strain with dissimilar cardiac and metabolic impact. In addition changes in blood pressure values and electrolyte metabolism may occur.
Therefore it was of interest to study blood pressure and ionized magnesium values as stress markers.
Design and method:
Out of 100 microlitres of capillary blood from 23 parachuters and of 15 bungee jumpers sampled before and after the jump, blood glucose and ionized magnesium concentrations were determined by a NOVA Phox-M device, distributed by TECOM, Austria. Blood pressure values were measured by Beurer Instrumentation, Ulm, Germany.
Results:
1. Parachuting:
Sytolic and diastolic blood pressure values increased significantly after the jump (p < 0.01).
Heart rate did not change significantly.
Blood glucose and ionized magnesium values decreased significantly from initially high normal values (p < 0.01).
2. Bungee jumping:
Also no difference in heart rate, but a slight fall in systolic and a significant fall in diastolic blood pressure values after the jump were noted (p < 0.01).
Blood glucose increased from already high basal levels and ionized magnesium values decreased significantly (p < 0.01).
Conclusions:
Outright stress determines the sympathoadrenal anticipation, epinephrine challenge should be not dissimilarly high. However, a longer anxiety period during the para-jump proceedings could lead to time dependent contrary reactions in blood pressure, magnesium and glucose levels, all of them stress markers of different sensibility.
Taken together:
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