The role of endothelins in the regulation of vascular tone in the
in situ perfused rat adrenals.
Mazzocchi, Giuseppina, Ludwik K. Malendowicz, Francesco G. Musajo,
Giuseppe Gottardo, Anna Markowska, and Gastone G. Nussdorfer.
Department of Anatomy, University of Padua, I-35121 Padua, Italy,
and Department of Histology and Embryology, School of Medicine,
Poznan, Poland
APStracts 4:0207E, 1997.
This study examined the role of endothelins (ETs) and their receptor
subtypes ETA and ETB in the regulation of vascular tone in the in
situ perfused rat left adrenal gland. ET-1, that binds both ETA and
ETB receptors, decreased adrenal flow rate of the perfusion medium,
and its effect was reversed by the ETA antagonist BQ-123 and enhanced
by the ETB antagonist BQ-788. ET-3, that preferentially binds ETB,
and the selective ETB agonist BQ-3020 increased adrenal flow rate of
perfusate, and their effects were annulled by BQ-788. BQ-123
magnified the effect of ET-3, and did not affect that of BQ-3020. The
ETA-mediated decrease and the ETB-mediated rise in the rate of
collection of perfusate were abolished by Ro31-8220, an inhibitor of
protein kinase C (PKC), and L-NAME, an inhibitor of nitric oxide
synthase (NOS), respectively. Collectively, these findings suggest
that ETs can regulate vascular tone in the in situ perfused rat
adrenals, via both PKC-coupled ETA and NOS-coupled ETB receptors,
whose activation evokes vasoconstriction and vasodilation,
respectively.
Received 15 April 1997; accepted in final form 17 September 1997.
APS Manuscript Number E171-7.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 7 October 1997