Effect of Equol on Vasocontractions in Rat Carotid Arteries Treated with High Insulin
| Autor: | Mihoka Kojima, Kumiko Taguchi, Keisuke Takayanagi, Shota Kobayashi, Takayuki Matsumoto, Tsuneo Kobayashi |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Male
0301 basic medicine Agonist Serotonin medicine.medical_specialty Vascular smooth muscle Contraction (grammar) Thromboxane medicine.drug_class medicine.medical_treatment Pharmaceutical Science Phytoestrogens Muscle Smooth Vascular Norepinephrine 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Internal medicine medicine Animals Insulin Large-Conductance Calcium-Activated Potassium Channels Rats Wistar Receptor Pharmacology food and beverages General Medicine Equol Iberiotoxin Carotid Arteries 030104 developmental biology Endocrinology chemistry Vasoconstriction 030220 oncology & carcinogenesis Potassium |
| Zdroj: | Biological and Pharmaceutical Bulletin. 42:1048-1053 |
| ISSN: | 1347-5215 0918-6158 |
| DOI: | 10.1248/bpb.b19-00051 |
| Popis: | Previous research has indicated that high insulin affects vascular function. Equol is an active metabolite of daidzein, an isoflavone produced from soy by intestinal microbial flora, with beneficial effects on the vascular system. This study investigated whether equol was beneficial for vascular function under high insulin conditions. Using organ culture techniques, rat carotid arteries were treated for 23 ± 1 h with a vehicle, high insulin (100 nM), or equol (100 µM) plus high insulin (100 nM). Vascular isometric forces were measured by the organ bath technique. In each endothelium-intact ring, the contractions induced by high-K+, noradrenaline, or by serotonin (5-HT) were similar for the vehicle, insulin, and equol + insulin treatments. Contractions induced by a selective 5-HT2A receptor agonist (TCB2) increased with insulin treatment (vs. vehicle), but less so with equol + insulin. Under basal conditions, a selective 5-HT2B receptor agonist (BW723C86) did not induce contraction; following precontraction by a thromboxane analog, it induced contraction but not relaxation. These responses were similar across the three treatments. Acetylcholine-induced relaxations were also similar for the three treatments. In the endothelium-denuded preparations, 5-HT-induced contraction was augmented with insulin treatment (vs. vehicle) but less so by equol + insulin treatment. These differences in 5-HT-induced contractions were eliminated by iberiotoxin, a large-conductance calcium-activated K+ channel (BKCa) inhibitor. These results suggest that equol exerts a preventive effect on the enhancement of 5-HT-induced contraction by high insulin (possibly mediated by the 5-HT2A receptor), and that these effects may be attributed to the activation of BKCa channels in vascular smooth muscle. |
| Databáze: | OpenAIRE |
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