Related resources
Search for item elsewhere
University researcher(s)
Academic department(s)
Diabetic dyslipidemia and exercise affect coronary tone and differential regulation of conduit and microvessel K+ current.
Mokelke E, Dietz N, Eckman D, Nelson MT, Sturek M
American Journal of Physiology-Heart and Circulatory Physiology. 2005;288( 3):H1233-41.
Access to files
Full-text and supplementary files are not available from Manchester eScholar. Use our list of Related resources to find this item elsewhere. Alternatively, request a copy from the Library's Document supply service.
Abstract
Spontaneous transient outward K(+) currents (STOCs) elicited by Ca(2+) sparks and steady-state K(+) currents modulate vascular reactivity, but effects of artery size, diabetic dyslipidemia, and exercise on these differentially regulated K(+) currents are unclear. We studied the conduit arteries and microvessels of male Yucatan swine assigned to one of three groups for 20 wk: control (C, n = 7), diabetic dyslipidemic (DD, n = 6), or treadmill-trained DD animals (DDX, n = 7). Circumflex artery blood flow velocity obtained with intracoronary Doppler and lumen diameters obtained by intravascular ultrasound enabled calculation of absolute coronary blood flow (CBF). Ca(2+) sparks were determined in pressurized microvessels, and perforated patch clamp assessed K(+) current in smooth muscle cells isolated from conduits and microvessels. Baseline CBF in DD was decreased versus C. In pressurized microvessels, Ca(2+) spark activity was significantly lower in DD versus C and DDX (P < 0.05 vs. DDX). STOCs were pronounced in microvessel (approximately 35 STOCs/min) in sharp contrast to conduit cells ( approximately 2 STOCs/min). STOCs were decreased by 86% in DD versus C and DDX in microvessels; in contrast, there was no difference in STOCs across groups in conduit cells. Steady-state K(+) current in microvessels was decreased in DD and DDX versus C; in contrast, steady-state K(+) current in conduit cells was decreased in DDX versus DD and C. We conclude that steady-state K(+) current and STOCs are differentially regulated in conduit versus microvessels in health and diabetic dyslipidemia. Exercise prevented diabetic dyslipidemia-induced decreases in baseline CBF, possibly via STOC-regulated basal microvascular tone.
Keyword(s)
Animals; Male; Patch-Clamp Techniques; Swine; Swine, Miniature; metabolism: Potassium; physiology: Calcium Signaling; physiology: Coronary Circulation; physiology: Microcirculation; physiology: Physical Conditioning, Animal; physiology: Potassium Channels; physiopathology: Diabetic Angiopathies; physiopathology: Hyperlipidemias