20-HETE Requires Increased Vascular Tone to Constrict Rabbit Afferent Arterioles

• Published in: Hypertension (Dallas, Tex. 1979) Vol. 27; no. 3; pp. 781 - 785
• Main Authors: Arima, Shuji, Omata, Ken, Ito, Sadayoshi, Tsunoda, Kazuo, Abe, Keishi
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Philadelphia, PA American Heart Association, Inc 01-03-1996; Hagerstown, MD Lippincott
• Subjects: Animals; Arachidonic Acid - physiology; Arterioles - physiology; Biological and medical sciences; Blood vessels and receptors; Fundamental and applied biological sciences. Psychology; Hydroxyeicosatetraenoic Acids - administration & dosage; Hypertension - etiology; Kidney - blood supply; Kidney - physiology; Male; Rabbits; Vascular Resistance - drug effects; Vertebrates: cardiovascular system
• ISSN: 0194-911X; 1524-4563
• DOI: 10.1161/01.hyp.27.3.781

Renal production of 20-hydroxyeicosatetraenoic acid (20-HETE), a cytochrome P-450-dependent arachidonate metabolite, increases during development of hypertension in spontaneously hypertensive rats, and inhibition of its production prevents hypertension. Since 20-HETE is a potent vasoconstrictor, these findings suggest that 20-HETE may contribute to the development of hypertension by elevating renal vascular resistance. In this study we examined the direct action of 20-HETE on the afferent arteriole, a vascular segment crucial to the control of renal vascular resistance. Rabbit afferent arterioles were microperfused at 60 mm Hg in vitro, and 20-HETE was added to the lumen. Although 20-HETE (10 to 10 mol/L) had no effect on the diameter of non-treated afferent arterioles (n = 6), it caused dose-dependent constriction when vascular tone was increased with norepinephrine (0.3 micro mol/L); 20-HETE at 10 () mol/L decreased diameter by 43 plus/minus 4% (n = 6, P < .001). This constriction was abolished by disrupting the endothelium (n = 5). Moreover, pretreatment with the cyclooxygenase inhibitor indomethacin (50 micro mol/L) or the thromboxane/endoperoxide receptor antagonist SQ29548 (1 micro mol/L) significantly (P < .03) attenuated 20-HETE-induced constriction20-HETE at 10 mol/L constricted norepinephrine-treated afferent arterioles by 28 plus/minus 3% (n = 6) and 25 plus/minus 4% (n = 5), respectively. These results demonstrate that an increase in afferent arteriolar tone is required for the vasoconstrictor action of 20-HETE, which is partly mediated by the endothelial cyclooxygenase pathway. Thus, increased production of 20-HETE in the kidney and increase in afferent arteriolar tone, both of which often precede the development of hypertension, may synergistically contribute to the development of hypertension by elevating renal vascular resistance. (Hypertension. 1996;27[part 2]:781-785.)