Biomedical Engineering Reference
In-Depth Information
[
1135
]. Hemodynamic stresses stimulate secretion of PDGFbb and IL1
by
endothelial cells and subsequent SMC migration, whereas lower levels of shear
stress and cyclic strain have no effect.
α
9.10.6.7
T2-Tryptophanyl-tRNA Synthase
T2
Tryptophanyl-tRNA synthase (
T2
TrpRS), a natural fragment of TrpRS, inhibits
flow-induced activation of PKB, ERK1 and ERK2, and NOS [
1136
]. It hinders
endothelial cell elongation and alignment of stress fibers and microtubules in the
flow direction. In addition,
T2
TrpRS is an antagonist of VEGF-induced angiogene-
sis. It binds at intercellular junctions of endothelial cells to cadherin-5 [
1137
], but
complete TrpRS remains inactive.
9.10.7
Other Aspects of the Regulation of the Vasomotor Tone
9.10.7.1
Nitroglycerin
Nitroglycerin is a potent vasodilator at low dose (1-10 nmol) that activates nitric
oxide synthase, although it can be converted into NO and/or other vasoactive
compounds [
1138
].
178
Very small doses of nitroglycerin (comparable to basal level
of free NO, i.e., 5-20 nmol) actually cause rapid vasodilation after administration
(1-3 mn after administration), hence suggesting NO production by NOS1 and NOS3
rather than nitroglycerin conversion into vasoactive substances.
179
At higher dose,
nitroglycerin exerts its effect via metabolites.
9.10.7.2
Secretoneurin
Secretoneurin belongs to the secretogranin-2 family. It enhances adhesion and
transendothelial migration of monocytes. In porcine coronary arteries, after acute
exposure, secretoneurin relaxes via activation of endothelial nitric oxide synthase
(NOS3) and cyclooxygenase, nitric oxide being the dominant agent [
1139
]. During
prolonged administration (24 h), secretoneurin enhanced the relaxation caused by
bradykinin.
178
Xanthine oxidase and mitochondrial aldehyde dehydrogenase mediate nitroglycerin reduction
to nitrite and NO.
179
Nitroglycerin induces phosphorylation of NOS1 at Ser852 and NOS3 at Ser1177 in rats and
mice.
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