Identification of capric acid as a potent vasorelaxant of human basilar arteries

Abstract

To determine whether naturally occurring fatty acids, especially saturated ones, might act directly as vasodilators, segments of human basilar arteries and umbilical arteries were precontracted submaximaHy with prostaglandin F2α and then exposed to different saturated fatty adds (C4 through C16) or unsaturated fatty acids (04:1, CIS: 1, 08:2, and 08:3) at concentrations from 4 μM to 4 mM, The results showed caprate (CIO) to be the most potent vasorelaxant and basilar arteries to be more responsive (EC50=63 μM) than umbilical arteries (EC50=780 μM). Caprate also inhibited contractions elicited by KCI, serotonin, and the thromboxane analogue L46619. The relaxation was independent of the endothelium, and potency was not related to the weak capacity of caprate to inhibit Ca2+-induced contractions of K+ -depolarized basilar arteries. The pattern of potencies for the arteries differed, but among unsaturated fatty acids the monounsaturated (04:1, C18:l) were more potent than the polyunsaturated (08:2, 08:3). Comparing the potencies obtained with the concentrations reported for the free fatty acid content of arteries, brain, and plasma indicates that these lipids could influence vasomotion in health and disease. © 1991 American Heart Association, Inc.