Vascular Reactivity in Arterioles From Normal and Alloxan-Diabetic Mice
Studies on Single Perfused Islets
- 1Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
- 2Johannes-Müller Institute of Physiology, University Hospital Charité, Humboldt University of Berlin, Berlin, Germany
- Address correspondence and reprint requests to Leif Jansson, Department of Medical Cell Biology, Biomedical Centre, Box 571, SE-751 23 Uppsala, Sweden. E-mail: leif.jansson{at}medcellbiol.uu.se
Abstract
Pancreatic islets possess an autonomous mechanism of blood flow regulation, independent of that of the exocrine pancreas. To study islet vascular regulation without confounding effects of the exocrine blood vessels, we have developed a technique enabling us to isolate single pancreatic islets and then to perfuse them using their endogenous vasculature for distribution of the medium. This made it possible to directly study the vascular reactivity of islet arterioles to different substances. We confirmed that control of islet blood flow is mainly located at the precapillary level. As expected, administration of angiotensin II and l-nitro-arginine methyl ester contracted islet arterioles, whereas nitric oxide and adenosine dilated them. d-glucose, the main insulin secretagogue, had a selective dilating effect on smooth muscle in islet arterioles but not in glomerular afferent arterioles. The response to glucose was amplified in islet arterioles from diabetic animals, indicating enhanced islet blood perfusion in diabetes. This newly developed technique for perfusing isolated pancreatic islets will provide new insights into islet perfusion control and its possible contributions to the pathogenesis of type 2 diabetes.
Footnotes
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Ang II, angiotensin II; l-NAME, l-nitro-arginine methyl ester; VSM, vascular smooth muscle cell.
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- Accepted October 13, 2006.
- Received May 5, 2006.
- DIABETES
