Effects of the combined ETA and ETB receptor antagonist PD145065 on arteries, arterioles, and veins in the cat hindlimb

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Effects of the combined ETA and ETB receptor antagonist PD145065 on arteries, arterioles, and veins in the cat hindlimb. / Ekelund, Ulf; Adner, Mikael; Edvinsson, Lars; Mellander, Stefan.

I: Journal of Cardiovascular Pharmacology, Vol. 26, Nr. Suppl. 3, 1995, s. 211-213.

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

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T1 - Effects of the combined ETA and ETB receptor antagonist PD145065 on arteries, arterioles, and veins in the cat hindlimb

AU - Ekelund, Ulf

AU - Adner, Mikael

AU - Edvinsson, Lars

AU - Mellander, Stefan

PY - 1995

Y1 - 1995

N2 - The aim of this study was to describe in quantitative terms the effects of ETA and ETB receptor blockade on vascular tone (resistance) in large-bore arterial resistance vessels (> 25 microns), small arterioles (< 25 microns), and veins in the cat gastrocnemius muscle in vivo. In the muscle vascular bed, the combined ETA and ETB receptor antagonist PD145065 (1 mg/kg/min, intra-arterially) abolished the biphasic vascular responses (dilatation followed by constriction) to both ET-1 (0.4 microgram/kg/min, intra-arterially) and to the selective ETB receptor agonist IRL1620 (3.2 micrograms/kg/min, intra-arterially). In the cat femoral artery and vein in vitro, PD145065 competitively inhibited the contractile responses to both ET-1 and IRL1620. The contractile response to the latter agonist could be evoked only after long-term incubation of the vessels (37 degrees C for 5 days). These results indicate that PD145065 is a potent antagonist at both ETA and ETB receptors in vivo and in vitro. Therefore, this antagonist may prove useful for elucidating the possible physiologic and/or pathophysiologic roles of the endothelins. For example, it was shown that PD145065 had no effect on vascular tone in the resting state, indicating no role for the endothelins in the regulation of basal vascular tone in cat skeletal muscle.

AB - The aim of this study was to describe in quantitative terms the effects of ETA and ETB receptor blockade on vascular tone (resistance) in large-bore arterial resistance vessels (> 25 microns), small arterioles (< 25 microns), and veins in the cat gastrocnemius muscle in vivo. In the muscle vascular bed, the combined ETA and ETB receptor antagonist PD145065 (1 mg/kg/min, intra-arterially) abolished the biphasic vascular responses (dilatation followed by constriction) to both ET-1 (0.4 microgram/kg/min, intra-arterially) and to the selective ETB receptor agonist IRL1620 (3.2 micrograms/kg/min, intra-arterially). In the cat femoral artery and vein in vitro, PD145065 competitively inhibited the contractile responses to both ET-1 and IRL1620. The contractile response to the latter agonist could be evoked only after long-term incubation of the vessels (37 degrees C for 5 days). These results indicate that PD145065 is a potent antagonist at both ETA and ETB receptors in vivo and in vitro. Therefore, this antagonist may prove useful for elucidating the possible physiologic and/or pathophysiologic roles of the endothelins. For example, it was shown that PD145065 had no effect on vascular tone in the resting state, indicating no role for the endothelins in the regulation of basal vascular tone in cat skeletal muscle.

M3 - Article

VL - 26

SP - 211

EP - 213

JO - Journal of Cardiovascular Pharmacology

JF - Journal of Cardiovascular Pharmacology

SN - 1533-4023

IS - Suppl. 3

ER -