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Hashimoto M, Shinozuka K, Shahdat HM, Kwon YM, Tanabe Y, Kunitomo
M, Masumura S. Antihypertensive effect of all-cis-5,8,11,14,17-icosapentaenoate
of aged rats is associated with an increase in the release of ATP from
the caudal artery. J Vasc Res. 1998;Jan-Feb;35(1):55-62.
Department of Physiology, Shimane Medical University, Izumo,
Japan.
Fish oils have been shown to lower blood pressure in hypertensive subjects.
All-cis-5,8,11,14,17-icosapentaenoate (EPA), one of the omega-3 polyunsaturated
fatty acids, is known to be one of the major active components in fish
oil that has beneficial effects on the cardiovascular system. However,
little is known about the antihypertensive effect of EPA alone on blood
pressure. In the present study, we have determined the spontaneous and
noradrenaline-evoked release of ATP, ADP, AMP, and adenosine from caudal
arteries of aged (100 weeks old) Wistar rats which were fed a standard
diet or a high cholesterol diet, treated with EPA. Dietary EPA administration
increased plasma and caudal arterial EPA concentrations and repressed
increases in blood pressure with advancing age in both aged rats with
and without hypercholesterolemia. In addition, noradrenaline (1 micromol/l)
evoked a significantly greater release of purines from the caudal arteries
of EPA-administered aged rats compared to both sets of control rats.
Regression analysis revealed a significant relationship between the total
amount of purines released from the artery and blood pressure. These
results suggest that administration of EPA to aged rats increases the
release of ATP from the vascular endothelial cells, leading to repression
of the blood pressure rise seen with advancing age.
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Abstracts