Plasma microdialysis. A technique for continuous plasma sampling in freely moving rats.
Microdialysis provides a means of continuous plasma sampling without repeated blood drawing. We report here the use of a specially designed and constructed microdialysis probe to sample plasma glucose, protein, and luteinizing hormone from the right atrium of a freely moving rat. Our probe has a unique side-arm tubing, which can be used to draw blood for in vivo probe calibration and infuse heparin continuously to prevent blood clotting. Glucose recovery rate (18%) of the probe remained relatively stable in continuously heparinized rats over 24 hr, but it dropped rapidly to 1% in nonheparinized rats. The concentration of plasma glucose was significantly underestimated, when it was converted from the perfusate concentration based on the in vitro, but not in the in vivo, recovery rate of the probe. The recovery of plasma protein was only 0.07% initially and rapidly declined to about 0.03%. Luteinizing hormone was not detected in the perfusates from either normal or luteinizing hormone-releasing hormone-stimulated rats. These results indicate that continuous heparinization and in vivo probe calibration are essential for successful plasma microdialysis, and our current dialysis membrane can be used to sample non-protein-bound molecules in the plasma.
Chen
Z
Z
Department of Physiology, Southern Illinois University, School of Medicine, Carbondale 62901-6512.
Steger
R W
RW
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001798:Blood Proteins / Q000032:analysis; D001800:Blood Specimen Collection / Q000379:methods*; D002404:Catheterization / Q000379:methods; D005260:Female; D007003:Hypoglycemia / Q000097:blood / Q000139:chemically induced; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D006435:Renal Dialysis / Q000379:methods*
D001786:Blood Glucose; D001798:Blood Proteins; D007986:Luteinizing Hormone