Central and peripheral administration of endothelin-1 induces an increase in blood pressure in conscious trout.
The central and peripheral cardiovascular effects of endothelin (ET)-1 and ET-3 were investigated in conscious rainbow trout. Both intracerebroventricular and intra-arterial injections of ET-1 (6. 25-25 pmol) but not ET-3 (25 pmol) caused a dose-dependent increase in mean dorsal aortic blood pressure and a concomitant decrease in heart rate. The hypertensive effects induced by intra-arterial and intracerebroventricular injection of ET-1 were associated with a significant (P < 0.05) increase in systemic vascular resistance. Intracerebroventricular injection of ET-1 induced a twofold higher pressor response than that caused by intra-arterial injection of ET-1 and provoked a barostatic gain that was reduced by 2.5- to 3-fold compared with that calculated after intra-arterial administration of the peptide. The ET receptor antagonist bosentan significantly (P < 0.05) attenuated these responses regardless of the route of administration. Finally, intra-arterial injection of ET-1 did not significantly modify plasma cortisol level. The present data demonstrate that intracerebroventricular and intra-arterial administration of very low doses of ET-1 produces hypertension in conscious trout. The lack of effect of ET-3 indicates that the hemodynamic actions of ET-1 are mediated both centrally and peripherally through ETA receptors.
le Mével
J C
JC
Laboratoire de Neurophysiologie, Unité de Formation et de Recherche de Médecine, Université de Bretagne Occidentale, 29285 Brest Cedex, France. jean-claude.lemevel@univbrest.fr
Delarue
C
C
Mabin
D
D
Vaudry
H
H
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects*; D000077300:Bosentan; D002302:Cardiac Output / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000008:administration & dosage* / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D006854:Hydrocortisone / Q000097:blood; D007269:Injections, Intra-Arterial; D007276:Injections, Intraventricular; D017686:Oncorhynchus mykiss / Q000097:blood / Q000502:physiology*; D013449:Sulfonamides / Q000494:pharmacology
D000959:Antihypertensive Agents; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D013449:Sulfonamides; D000077300:Bosentan; D006854:Hydrocortisone