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Anti‐Contractile Effect of Perivascular Adipose Tissue in Pregnant Rat Aorta
Author(s) -
Oriowo Mabayoje,
AlJarallah Aishah
Publication year - 2015
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.29.1_supplement.783.1
Subject(s) - aorta , endocrinology , medicine , contraction (grammar) , isometric exercise , adipose tissue , chemistry
It is now known that PVAT releases a variety of factors and inhibits contraction induced by a variety of vasoconstrictors. The present investigation examines the effect of pregnancy on the anti‐contractile effect of PVAT. Aorta segments, with or without PVAT, from non‐pregnant and pregnant rats were set up in tissue baths for isometric tension recording. 5‐Hydroxytryptamine (5‐HT) induced concentration‐dependent contractions were reduced in aorta segments with PVAT attached but this anti‐contractile effect of PVAT was impaired in segments from pregnant rats. 4‐AP, inhibitor of Kv channels, enhanced 5‐HT‐induced contractions of aorta segments from pregnant and non‐pregnant rats only when PVAT was attached suggesting modulation of 5‐HT‐induced contraction by a substance (ADRF) released by PVAT which subsequently activated Kv channels to produce an anti‐contractile effect. There was no significant difference between the potentiating effects of 4‐AP on 5‐HT‐induced contractions in aorta segments (with PVAT) from pregnant and non‐pregnant rats. This is consistent with the fact that there was no significant difference in the expression of Kv7 channels in aorta segments (with PVAT) from pregnant and non‐pregnant rats. This would rule out impaired expression and function of Kv channels as the underlying factor for the loss of anti‐contractile effect of PVAT. It was therefore concluded that the loss of anti‐contractile effect of PVAT in aorta segments from pregnant rats may be due to the release of a contracting factor or loss of a relaxing factor by PVAT. Supported by a grant (MR 01/12) from Kuwait University Research sector