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Differing effects of histamine and serotonin on microvascular permeability in anaesthetized rats
Author(s) -
Michel C. C.,
Kendall S.
Publication year - 1997
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.1469-7793.1997.657bm.x
Subject(s) - histamine , serotonin , chemistry , perfusion , permeability (electromagnetism) , endocrinology , medicine , vascular permeability , endothelium , oncotic pressure , biophysics , biochemistry , biology , receptor , membrane , albumin
1 We have investigated simultaneous changes in the hydraulic permeability ( L p ) and the retention of perfusate macromolecules in single mesenteric venules of anaesthetized rats during perfusion with either histamine or serotonin. 2 The venules were microperfused in situ. Retention of macromolecules was assessed from the effective oncotic pressure (σΔπ) exerted by the perfusate across the vessel walls. L p and σΔπ were estimated by the red cell microperfusion technique. 3 Perfusion with histamine (at concentrations between 16 μ m and 3.26 m m ) and serotonin (at concentrations between 26 μ m and 1.3 m m ) transiently increased L p and reduced σΔπ Maximal changes were seen at 6–9 min with histamine and at 3 min with serotonin. 4 Maximal increases in L p were greater with histamine (approximately 3 ‐fold) than with serotonin (1.5‐ to 2‐fold). Serotonin, however, decreased σΔπ from a baseline of 14–15 cm H 2 O to one of 6–7 cm H 2 O whereas the fall of σΔπ with histamine was only from 14–15 cm H 2 O to 10–11 cm H 2 O. 5 The data are consistent with the hypothesis that serotonin increases permeability by inducing openings in the venular endothelium which do not retain macromolecules. If histamine also increases permeability by gap formation, these gaps are able to retain macromolecules to a significant extent.