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Contraction stimulates nitric oxide independent microvascular recruitment and increases muscle insulin uptake


Inyard, AC and Clerk, LH and Vincent, MA and Barrett, EJ, Contraction stimulates nitric oxide independent microvascular recruitment and increases muscle insulin uptake , Diabetes, 56, (9) pp. 2194-2200 . ISSN 0012-1797 (2007) [Refereed Article]

DOI: doi:10.2337/db07-0020


We examined whether contraction-induced muscle microvascular recruitment would expand the surface area for insulin and nutrient exchange and thereby contribute to insulin-mediated glucose disposal. We measured in vivo rat hindlimb microvascular blood volume (MBV) using contrast ultrasound and femoral blood flow (FBF) using Doppler ultrasound in response to a stimulation frequency range. Ten minutes of 0.1-Hz isometric contraction more than doubled MBV (P < 0.05; n = 6) without affecting FBF (n = 7), whereas frequencies >0.5 Hz increased both. Specific inhibition of nitric oxide (NO) synthase with N-L-nitro-arginine-methyl ester (n = 5) significantly elevated mean arterial pressure by 30 mmHg but had no effect on basal FBF or MBV. We next examined whether selectively elevating MBV without increasing FBF (0.1-Hz contractions) increased muscle uptake of albumin-bound Evans blue dye (EBD). Stimulation at 0.1 Hz (10 min) elicited more than twofold increases in EBD content (micrograms EBD per gram dry tissue) in stimulated versus contralateral muscle (n = 8; 52.2 3.8 vs. 20 2.5, respectively; P < 0.001). We then measured muscle uptake of EBD and 125I-labeled insulin (dpm per gram dry tissue) with 0.1-Hz stimulation (n = 6). Uptake of EBD (19.1 3.8 vs. 9.9 1; P < 0.05) and 125I-insulin (5,300 800 vs. 4,244 903; P < 0.05) was greater in stimulated muscle versus control. Low-frequency contraction increases muscle MBV by a NO-independent pathway and facilitates muscle uptake of albumin and insulin in the absence of blood flow increases. This microvascular response may, in part, explain enhanced insulin action in exercising skeletal muscle.

Item Details

Item Type:Refereed Article
Research Division:Biomedical and Clinical Sciences
Research Group:Clinical sciences
Research Field:Endocrinology
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:Vincent, MA (Dr Michelle Keske)
ID Code:62763
Year Published:2007
Web of Science® Times Cited:62
Deposited By:Menzies Institute for Medical Research
Deposited On:2010-03-22
Last Modified:2010-05-03

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