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The vasodilatory peptide maxadilan increases vascular permeability due to activation of leukocytes in postcapillary venules
Author(s) -
Svensjo Erik,
Cruz Vanessa,
Saraiva Elvira M,
Bozza Marcelo T,
Lerner Ethan A,
Scharfstein Julio
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.590.7
Subject(s) - chemistry , vascular permeability , cheek pouch , dextran , venule , vasodilation , saline , receptor , biophysics , hamster , microcirculation , medicine , chromatography , biochemistry , biology
The vasodilatory peptide maxadilan (MAX) isolated from the sand fly Lutzomyia longipalpis induces plasma leakage in postcapillary venules of the hamster cheek pouch (HCP) via PAC‐1‐receptor stimulation. Here we studied arteriolar dilation, plasma leakage (FITC‐dextran 150) and accumulation of rhodamine‐labeled leukocytes in the HCP induced by topical applications of MAX 134 nM alone or combined with 8 μM M‐65, a PAC1‐receptor antagonist. Arteriolar diameter, plasma leakage (FITC‐fluorescence) and leukocyte accumulation (rhodamine‐fluorescence) was measured in digital camera images with a computer software (AxioVision 4.4). Four groups of hamsters, saline control, MAX 134 nM, MAX + M‐65 and FITC‐dextran 40 + MAX were studied. Applications of MAX and M‐65 were made topically to the HCPs in 250 μl of saline and images were recorded for 60 minutes. There was no plasma leakage increase in the saline control group but a slight increase in leukocyte accumulation. In contrast there was a lasting increase in plasma leakage (180%, P < 0.05) and leukocyte accumulation (150%, P < 0.05) in the MAX‐group with peak responses at 40 min and 60 min, respectively, that was inhibited by M‐65 and FITC‐dextran 40. M‐65 also inhibited arteriolar dilation while there was no significant inhibition of dilation in the FITC‐dextran 40 group. Conclusion: PAC1‐receptor activation by maxadilan causes plasma leakage and leukocyte accumulation independent of its vasodilatory effect.