[Effects of arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid on tension of rabbit aortic strips].
The purpose of the investigation was to determine the effects of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA) on the isolated rabbit aortic strips. The results showed that (1) the rabbit aortic strips with intact endothelium contracted in a dose-dependent manner to exogenous AA between the concentrations of 2.5 x 10(-6) mol/L and 4 x 10(-5) mol/L. EPA did not affect the tension of the relaxing strips, but inhibited the contractile response to AA (2 x 10(-5) mol/L), IC50 = 9.94 x 10(-6) mol/L. DHA showed no significant effect on the contractile response to AA. (2) In the endothelium-damaged rabbit aorta, the contraction of strips to AA was drastically diminished. The inhibitory effect of EPA on the contraction to AA was almost vanished. (3) The contraction of rabbit aortic strips to AA was shown to be abolished by indomethacin (1.5 x 10(-5) mol/L), a cyclooxygenase inhibitor. (4) Radioimmunoassay showed that exogenous AA increased the tissue levels of 6-keto-PGF1 alpha, TXB2 and their ratio. Lower dose of EPA (1.5 x 10(-6) or 1.5 x 10(-5) mol/L) did not affect the tissue levels of 6-keto-PGF1 alpha and TXB2. However, EPA at higher concentrations decreased the metabolites of AA significantly. These findings suggest that exogenous AA induces the contraction of rabbit aortic strips in vitro, which is related to the endothelial cells and mediated by the metabolites(s) of cyclooxygenase, likely endothelium-derived contracting factor (EDCF).(ABSTRACT TRUNCATED AT 250 WORDS)
Qi
A D
AD
Department of Pharmacology, Shandong Medical University, Jinan.
Wu
B J
BJ
Zhou
X B
XB
D015121:6-Ketoprostaglandin F1 alpha / Q000096:biosynthesis; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism; D001095:Arachidonic Acids / Q000494:pharmacology*; D004281:Docosahexaenoic Acids / Q000494:pharmacology*; D015118:Eicosapentaenoic Acid / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000502:physiology; D005260:Female; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D011817:Rabbits; D013929:Thromboxane B2 / Q000096:biosynthesis
D001095:Arachidonic Acids; D004281:Docosahexaenoic Acids; D013929:Thromboxane B2; D015121:6-Ketoprostaglandin F1 alpha; D015118:Eicosapentaenoic Acid