Myogenic constriction of human coronary arterioles. Am J Physiol 1997 Jul;273(1 Pt 2):H257-64
Date
07/11/1997Pubmed ID
9249498DOI
10.1152/ajpheart.1997.273.1.H257Scopus ID
2-s2.0-0030837510 (requires institutional sign-in at Scopus site) 101 CitationsAbstract
Myogenic constriction is an important mechanism of blood flow regulation; however, it has never been demonstrated in the human coronary circulation. We examined responses of human coronary resistance vessels in vitro to changes in intraluminal pressure and evaluated the role of protein kinase C (PKC). Microvessels (passive diameter 44-227 microns) were dissected from atrial appendages obtained during cardiac surgery and studied under conditions of zero flow. In response to stepped increases in pressure, there was a graded response such that at 100 mmHg, vessels constricted to 55 +/- 4% of their passive diameter. There was an inverse relationship between vessel diameter and myogenic responsiveness. Basal tone was attenuated by inhibition of voltage-dependent calcium channels (VDCC) with diltiazem and by inhibition of PKC with calphostin C. Activation of PKC with phorbol 12-myristate 13-acetate (PMA) enhanced basal tone. Active myogenic constriction was also impaired by calphostin C and augmented by PMA. Arterioles from patients with hypertension demonstrated enhanced myogenic constriction compared with vessels from normotensive patients (0.55 +/- 0.04 vs. 0.74 +/- 0.03; P < 0.01). These results demonstrate myogenic constriction in the human coronary microcirculation. Regulation of extracellular calcium by VDCC and intracellular calcium by PKC are important in mediating the magnitude of basal tone and myogenic responsiveness of these vessels.
Author List
Miller FJ Jr, Dellsperger KC, Gutterman DDMESH terms used to index this publication - Major topics in bold
AdolescentAdult
Aged
Analysis of Variance
Arterioles
Blood Pressure
Calcium Channel Blockers
Calcium Channels
Cardiopulmonary Bypass
Child
Child, Preschool
Coronary Vessels
Endothelin-1
Enzyme Inhibitors
Humans
In Vitro Techniques
Infant
Infant, Newborn
Middle Aged
Muscle Tonus
Muscle, Smooth, Vascular
Naphthalenes
Protein Kinase C
Regression Analysis
Tetradecanoylphorbol Acetate
Vascular Resistance
Vasoconstriction
