KATP Channels and Pancreatic Islet Blood Flow in Anesthetized Rats
Increased Blood Flow Induced by Potassium Channel Openers
- Leif Jansson1,
- Mikael Kullin2,
- F. Anders Karlsson2,
- Birgitta Bodin1,
- John Bondo Hansen3 and
- Stellan Sandler1
- 1Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
- 2Department of Medical Sciences, Uppsala University, Uppsala, Sweden
- 3Novo Nordisk A/S, Måløv, Denmark
- Address correspondence and reprint requests to Dr. 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
KATP channels are important for insulin secretion and depolarization of vascular smooth muscle. In view of the importance of drugs affecting KATP channels in the treatment of diabetes, we investigated the effects of these channels on splanchnic blood perfusion in general and pancreatic islet blood flow in particular. We treated anesthetized Sprague-Dawley rats with the KATP channel openers diazoxide or NNC 55-0118 or the KATP channel closer glipizide. Both diazoxide and NNC 55-0118 dose-dependently increased total pancreatic and islet blood flow in the presence of moderate hyperglycemia, but had no effects on the blood perfusion of other splanchnic organs. Diazoxide markedly lowered the mean arterial blood pressure and thus increased vascular conductance in all organs studied. NNC 55-0118 had much smaller effects on the blood pressure. Glipizide did not affect total pancreatic blood flow, but decreased islet blood flow by 50% in the presence of hypoglycemia. We conclude that KATP channels actively participate in the blood flow regulation of the pancreatic islets and that substances affecting such channels may also influence islet blood flow.
- ELISA, enzyme-linked immunosorbent assay
- SUR, sulfonylurea receptor
- VSMC, vascular smooth muscle cell
Footnotes
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- Accepted May 12, 2003.
- Received February 13, 2003.
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