title: Effects of dried bonito (katsuobushi) and captopril, an angiotensin I-converting enzyme inhibitor, on rat isolated aorta: a possible mechanism of antihypertensive action.
abstract: In order to elucidate the mechanism of the antihypertensive action of dried bonito (katsuobushi), we compared the effects of dried bonito extracts with those of captopril, an angiotensin I-converting enzyme (ACE) inhibitor, on aorta preparations isolated from rats. Dried bonito extracts (3 x 10(-4) to 3 x 10(-3) g/ml) more potently relaxed contractions induced by norepinephrine (10(-7) M) than contractions induced by KCl (55.9 mM). Dried bonito extracts (3 x 10(-3) g/ml) slightly inhibited 10(-7) M angiotensin I-induced contractions. In contrast, captopril (10(-8) to 10(-7) M) did not affect 10(-7) M norepinephrine- or 55.9 mM KCl-induced contractions, but a higher concentration of captopril (10(-6) M) very slightly relaxed it. Captopril (10(-8) to 10(-6) M) markedly inhibited 10(-7) M angiotensin I-induced contractions in a concentration-dependent manner. These results suggest that antihypertensive mechanism of action induced by dried bonito involves direct action on vascular smooth muscle in addition to ACE-inhibitory activity.
authors.affiliation: Graduate School of Humanities and Science, Ochanomizu University, Tokyo, Japan.
authors.forename: Kazuyo
authors.initials: K
authors.lastname: Kouno
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Hirano
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kuboki
authors.forename: Midori
authors.initials: M
authors.lastname: Kasai
authors.forename: Keiko
authors.initials: K
authors.lastname: Hatae
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001011:Aorta / Q000187:drug effects; D002216:Captopril / Q000494:pharmacology*; D005396:Fish Products; D066298:In Vitro Techniques; D009638:Norepinephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D011189:Potassium Chloride; D002216:Captopril; D009638:Norepinephrine