Open AccessRegional Differences in the Effect of Oestrogen on Vascular Tone in Isolated Rabbit Arteries
Author(s) -
Opgaard Ole Saetrum,
Duckles Sue P.,
Krause Dia.
Publication year - 2002
Publication title -
pharmacology & toxicology
Language(s) - English
Resource type - Journals
eISSN - 1600-0773
pISSN - 0901-9928
DOI - 10.1034/j.1600-0773.2002.910206.x
Subject(s) - phenylephrine , vasoconstriction , medicine , aorta , thoracic aorta , endocrinology , circulatory system , blood vessel , artery , vasoconstrictor agents , contraction (grammar) , blood pressure
The aim of the study was to assess how oestrogen acutely affects the tone of isolated artery segments from different vascular beds in rabbit. Cumulative concentrations of 17β‐oestradiol were added to ring segments of thoracic aorta, pulmonary artery, ear artery and coronary arteries from adult male rabbits. Coronary arteries precontracted with potassium or the thromboxane agonist, U46619, relaxed to oestrogen (10 −7 to 10 −4 M), whereas oestrogen (10 −8 to 10 −4 M) only caused additional contraction in segments of thoracic aorta and pulmonary artery precontracted with phenylephrine. In the thoracic aorta both the phospholipase C inhibitor NCDC (10 −4 M) and the cyclooxygenase inhibitor indomethacin (10 −5 M) almost completely blocked the contractile effect of oestrogen. In segments of the ear artery, oestrogen caused relaxation only at higher concentrations of oestrogen (10 −5 to 10 −4 M). In conclusion, oestrogen may cause both relaxation and vasoconstriction in different vascular beds, and in the thoracic aorta the contractile effects of oestrogen may be mediated via inositol phosphate‐dependent pathways and release of prostaglandins.