Sodium hyperosmolarity of intestinal lymph causes arteriolar vasodilation in part mediated by EDRF.
This study evaluated 1) the effect of increased submucosal lymph osmolarity on the regulation of first-order (1A) and second-order (2A) intestinal arterioles and 2) the role of endothelium-derived relaxing factor (EDRF) in hypertonic-induced vasodilation. Increasing the submucosal lymph osmolarity from 280 to 400 mosM, in increments of 30 mosM, resulted in a dose-dependent dilation of 1A and 2A. A submucosal lymph tonicity of 340 mosM, as occurs during glucose and oleic acid absorption, caused dilation of 1A (118%) and 2A (124%) equivalent to that during absorptive hyperemia. The dilation caused by 400 mosM mannitol (137%) was similar to that with 340 mosM NaCl (131%) and approximately 70% of that with 400 mosM NaCl (152%). After EDRF blockade, the responses to sodium hypertonicity decreased by about one-half; blockade reduced mannitol-induced dilation by 22%. These results indicate that sodium hypertonicity, as occurs during absorption, can play a major role in absorptive hyperemia, and about one-half of the dilation is related to a sodium-coupled release of EDRF.
Steenbergen
J M
JM
Department of Physiology and Biophysics, School of Medicine, Indiana University, Indianapolis 46202.
Bohlen
H G
HG
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001160:Arterioles / Q000502:physiology; D006982:Hypertonic Solutions; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000098:blood supply*; D008196:Lymph / Q000378:metabolism*; D008297:Male; D008353:Mannitol / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000502:physiology*; D009994:Osmolar Concentration; D051381:Rats; D017207:Rats, Sprague-Dawley; D012462:Saline Solution, Hypertonic / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*; D014664:Vasodilation / Q000502:physiology*
D006982:Hypertonic Solutions; D012462:Saline Solution, Hypertonic; D009569:Nitric Oxide; D008353:Mannitol; D001120:Arginine; D012964:Sodium; D019331:NG-Nitroarginine Methyl Ester