HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 294/1/H21    most recent 00861.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Golub, A. S. Articles by Pittman, R. N. Search for Related Content PubMed PubMed Citation Articles by Golub, A. S. Articles by Pittman, R. N.

Microvascular oxygen tension in the rat mesentery

Department of Physiology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia

Submitted 23 July 2007 ; accepted in final form 18 October 2007

Longitudinal PO₂ profiles in the microvasculature of the rat mesentery were studied using a novel phosphorescence quenching microscopy technique that minimizes the accumulated photoconsumption of oxygen by the method. Intravascular oxygen tension (PO₂, in mmHg) and vessel diameter (d, in µm) were measured in mesenteric microvessels (n = 204) of seven anesthetized rats (275 g). The excitation parameters were as follows: 7 x 7-µm spot size; 410 nm laser; and 100 curves at 11 pulses/s, with pulse parameters of 2-µs duration and 80-pJ/µm² energy density. The mean PO₂ (± SE) was 65.0 ± 1.4 mmHg (n = 78) for arterioles (d = 18.8 ± 0.7 µm), 62.1 ± 2.0 mmHg (n = 38) at the arteriolar end of capillaries (d = 7.8 ± 0.3 µm), and 52.0 ± 1.0 mmHg (n = 88) for venules (d = 22.5 ± 1.0 µm). There was no apparent dependence of PO₂ on d in arterioles and venules. There were also no significant deviations in PO₂ based on d (bin width, 5 µm) from the general mean for both of these types of vessels. Results indicate that the primary site of oxygen delivery to tissue is located between the smallest arterioles and venules (change of 16.3 mmHg, P = 0.001). In conclusion, oxygen losses from mesenteric arterioles and venules are negligible, indicating low metabolic rates for both the vascular wall and the mesenteric tissue. Capillaries appear to be the primary site of oxygen delivery to the tissue in the mesenteric microcirculation. In light of the present results, previously reported data concerning oxygen consumption in the mesenteric microcirculation can be explained as artifacts of accumulated oxygen consumption due to the application of instrumentation having a large excitation area for PO₂ measurements in slow moving and stationary media.

microcirculation; phosphorescence quenching microscopy; oxygen partial pressure profiles; oxygen consumption

This article has been cited by other articles:

				B. Reglin, T. W. Secomb, and A. R. Pries Structural adaptation of microvessel diameters in response to metabolic stimuli: where are the oxygen sensors? Am J Physiol Heart Circ Physiol, December 1, 2009; 297(6): H2206 - H2219. [Abstract] [Full Text] [PDF]

				A. S. Golub and R. N. Pittman PO2 measurements in the microcirculation using phosphorescence quenching microscopy at high magnification Am J Physiol Heart Circ Physiol, June 1, 2008; 294(6): H2905 - H2916. [Abstract] [Full Text] [PDF]