Mechanism of coronary vasodilation to insulin and insulin-like growth factor I is dependent on vessel size. Am J Physiol Endocrinol Metab 2000 Jul;279(1):E176-81
Date
07/14/2000Pubmed ID
10893337DOI
10.1152/ajpendo.2000.279.1.E176Scopus ID
2-s2.0-23544478975 (requires institutional sign-in at Scopus site) 50 CitationsAbstract
Insulin and insulin-like growth factor I (IGF-I) influence numerous metabolic and mitogenic processes; these hormones also have vasoactive properties. This study examined mechanisms involved in insulin- and IGF-I-induced dilation in canine conduit and microvascular coronary segments. Tension of coronary artery segments was measured after constriction with PGF(2alpha). Internal diameter of coronary microvessels (resting diameter = 112.6+/-10.1 microm) was measured after endothelin constriction. Vessels were incubated in control (Krebs) solution and were treated with N(omega)-nitro-L-arginine (L-NA), indomethacin, or K(+) channel inhibitors. After constriction, cumulative doses of insulin or IGF-I (0.1-100 ng/ml) were administered. In conduit arteries, insulin produced modest maximal relaxation (32 +/- 5%) compared with IGF-I (66+/-12%). Vasodilation was attenuated by nitric oxide synthase (NOS) and cyclooxygenase inhibition and was blocked with KCl constriction. Coronary microvascular relaxation to insulin and IGF-I was not altered by L-NA, indomethacin, tetraethylammonium chloride, glibenclamide, charybdotoxin, and apamin; however, tetrabutylammonium chloride attenuated the response. In conclusion, insulin and IGF-I cause vasodilation in canine coronary conduit arteries and microvessels. In conduit vessels, NOS/cyclooxygenase pathways are involved in the vasodilation. In microvessels, relaxation to insulin and IGF-I is not mediated by NOS/cyclooxygenase pathways but rather through K(+)-dependent mechanisms.
Author List
Oltman CL, Kane NL, Gutterman DD, Bar RS, Dellsperger KCMESH terms used to index this publication - Major topics in bold
AnimalsCoronary Circulation
Coronary Vessels
Dogs
Female
Insulin
Insulin-Like Growth Factor I
Male
Microcirculation
Nitric Oxide Synthase
Potassium Channel Blockers
Potassium Channels
Potassium Chloride
Prostaglandin-Endoperoxide Synthases
Quaternary Ammonium Compounds
Vasoconstriction
Vasodilation