Capillary filtration coefficient is independent of number of perfused capillaries in cat skeletal muscle

• Published in: American journal of physiology. Heart and circulatory physiology 2001-06, Vol.280 (6), p.H2697-H2706
• Main Authors: Bentzer, Peter, Kongstad, Lis, Grande, Per-Olof
• Format: Article
• Language: English
• Subjects: Angiotensin II - pharmacology; Animals; Basic Medicine; Blood Flow Velocity - drug effects; Blood Pressure - drug effects; Blood Pressure - physiology; Capillaries - drug effects; Capillaries - physiology; Capillary Permeability - physiology; Cats; Electric Stimulation; Fysiologi; In Vitro Techniques; Medical and Health Sciences; Medicin och hälsovetenskap; Medicinska och farmaceutiska grundvetenskaper; Microcirculation - drug effects; Microcirculation - physiology; Microspheres; Muscle, Skeletal - blood supply; Muscle, Skeletal - physiology; Norepinephrine - pharmacology; Physiology; Reproducibility of Results; Sciatic Nerve - physiology; Vascular Resistance - drug effects; Vascular Resistance - physiology; Vasoconstriction - drug effects; Vasoconstriction - physiology; Vasoconstrictor Agents - pharmacology
• ISSN: 0363-6135; 1522-1539; 1522-1539
• DOI: 10.1152/ajpheart.2001.280.6.h2697

Department of Physiological Sciences and Department of Anesthesia and Intensive Care, University of Lund and University Hospital of Lund, SE-221 84 Lund, Sweden The capillary filtration coefficient (CFC) is assumed to reflect both microvascular hydraulic conductivity and the number of perfused capillaries at a given moment (precapillary sphincter activity). Estimation of hydraulic conductivity in vivo with the CFC method has therefore been performed under conditions of unchanged vascular tone and metabolic influence. There are studies, however, that did not show any change in CFC after changes in vascular tone and metabolic influence, and these studies indicate that CFC may not be influenced by alteration in the number of perfused capillaries. The present study reexamined to what extent CFC in a pressure-controlled preparation depends on the vascular tone and number of perfused capillaries by analyzing how CFC is influenced by 1 ) vasoconstriction, 2 ) increase in metabolic influence by decrease in arterial blood pressure, and 3 ) occlusion of precapillary microvessels by arterial infusion of microspheres. CFC was calculated from the filtration rate induced by a fixed decrease in tissue pressure. Vascular tone was increased in two steps by norepinephrine ( n  = 7) or angiotensin II ( n  = 6), causing a blood flow reduction from 7.2 ± 0.8 to at most 2.7 ± 0.2 ml · min 1 · 100 g 1 ( P