title: Flow modulates the transport of K+ through the walls of single perfused mesenteric venules in anaesthetised rats.
abstract: 1. We have investigated the effects of varying flow velocity (U) upon permeability to potassium ions (PK) of single perfused mesenteric venules in anaesthetised rats. PK was estimated using a development of the single bolus microperfusion technique at chosen flow velocities in the range of 300 to 6000 microm s-1. 2. In an initial study on 12 vessels, there was a strong positive correlation between PK and U. This was described by the relation: PK = 0.0053U + 8.86, where PK and U are both expressed in micrometres per second (microm s-1). 3. The addition of the nitric oxide (NO) synthase inhibitors (20 micromol l-1) N G-monomethyl-L-arginine (L-NMMA) and N G-nitro L-arginine (L-NNA) to the superfusate abolished the positive correlation between PK and U. The addition of D-NNA (20 micromol l-1) did not change the relation between PK and U where the median value for the slope of the relation was 57.7 (+/- 58.7 interquartile (IQR)) x 10-4 (n = 4). The addition of L-arginine (200 micromol l-1) restored the relation between PK and U where the slope of the relation was increased from 3.9 (+/- 16.3 IQR) x 10-4 to 69.2 (+/- 13.5 IQR) x 10-4 (n = 7). 4. The addition of the guanylate cyclase inhibitor LY83583 (10 micromol l-1) abolished the positive correlation between PK and U (n = 6). 5. Our data suggest that the flow modulates the potassium permeability through the walls of single perfused rat mesenteric venules via a NO-cGMP-dependent process.
authors.affiliation: Section of Cellular & Integrative Biology, Division of Biomedical Sciences, Imperial College School of Medicine, South Kensington, London, UK.
authors.forename: M
authors.initials: M
authors.lastname: Kajimura
authors.forename: C C
authors.initials: CC
authors.lastname: Michel
mesh_terms: D000465:Algorithms; D000634:Aminoquinolines / Q000494:pharmacology; D000758:Anesthesia; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects / Q000502:physiology; D002138:Calibration; D004058:Diffusion; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors; D066298:In Vitro Techniques; D007202:Indicators and Reagents; D008297:Male; D008642:Mesenteric Veins / Q000187:drug effects / Q000378:metabolism*; D008839:Microelectrodes; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052250:Nitric Oxide Synthase Type III; D019335:Nitroarginine / Q000494:pharmacology; D010477:Perfusion; D010539:Permeability; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000634:Aminoquinolines; D004791:Enzyme Inhibitors; D007202:Indicators and Reagents; D019335:Nitroarginine; C041715:6-anilino-5,8-quinolinedione; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D006162:Guanylate Cyclase; D011188:Potassium