Br J Ophthalmol 1998;82:826-829 ( July )
Role of the endothelium in modulating functional responses of
isolated bovine anterior ciliary arteries to vasoconstrictor agonists
Christine H Buckley,a b
Patrick W F Hadoke,b
Colm J O'Briena
a Department of
Ophthalmology, Royal Infirmary of Edinburgh, Edinburgh, b Department of
Medicine, Royal Infirmary of Edinburgh, Edinburgh
Correspondence to: Dr C H Buckley, Department of Medicine, Royal Infirmary of Edinburgh,
Lauriston Place, Edinburgh EH3 9YW.
; Accepted for publication 29 January 1998
BACKGROUND/AIMS
Endothelium
dependent vasodilatation is an important regulator of blood flow to the
eye but its role has not been investigated in vessels supplying the
ciliary body. This study assessed the role of the endothelium in
modulating vasoconstrictor responses of the intraocular bovine anterior
ciliary artery.
METHODSBovine
anterior ciliary arteries (n=33) were mounted in a myograph, containing
physiological salt solution at 37°C, for isometric force measurement.
Cumulative concentration-response curves were obtained to the
constrictor agonists 5-hydroxytryptamine (5-HT), noradrenaline,
phenylephrine, prostaglandin F2
, endothelin-1, and KCl
in both endothelium intact and denuded arteries.
RESULTSAll
vasoconstrictors produced sustained contractile responses which were
unaffected by the removal of the endothelium. Responses to 5-HT were
also unaffected by inhibition of nitric oxide synthase.
CONCLUSIONThese
results indicate that neither agonist stimulated nor basal release of
nitric oxide from the endothelium modulates responses to
vasoconstrictor agonists in the isolated bovine anterior ciliary artery
when measured in a no flow isometric system.
Keywords:
anterior ciliary artery;
constrictor agonists;
endothelium;
nitric oxide
© 1998 by British Journal of Ophthalmology
