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Flow modulates the transport of K + through the walls of single perfused mesenteric venules in anaesthetised rats
Author(s) -
Kajimura M.,
Michel C. C.
Publication year - 1999
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.1999.00665.x
Subject(s) - chemistry , biophysics , blood flow , physics , anesthesia , medicine , biology
1 We have investigated the effects of varying flow velocity ( U ) upon permeability to potassium ions ( P K ) of single perfused mesenteric venules in anaesthetised rats. P K was estimated using a development of the single bolus microperfusion technique at chosen flow velocities in the range of 300 to 6000 μm s −1 . 2 In an initial study on 12 vessels, there was a strong positive correlation between P K and U. This was described by the relation:
P K = 0·0053 U + 8 ·86,
where P K and U are both expressed in micrometres per second (μm s −1 ). 3 The addition of the nitric oxide (NO) synthase inhibitors (20 μmol 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 P K and U. The addition of D‐NNA (20 μmol l −1 ) did not change the relation between P K and U where the median value for the slope of the relation was 57·7 (± 58·7 interquartile (IQR)) × 10 −4 ( n = 4 ). The addition of L‐arginine (200 μmol l −1 ) restored the relation between P K and U where the slope of the relation was increased from 3·9 (± 16·3 IQR) × 10 −4 to 69·2 (± 13·5 IQR) × 10 −4 ( n = 7 ). 4 The addition of the guanylate cyclase inhibitor LY83583 (10 μmol l −1 ) abolished the positive correlation between P K 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.