Mechanisms of the pressor response to intravenous thyrotropin-releasing hormone in the rat.

Détails

ID Serval
serval:BIB_2A88CB2BFA79
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Mechanisms of the pressor response to intravenous thyrotropin-releasing hormone in the rat.
Périodique
Clinical and experimental pharmacology & physiology
Auteur(s)
Evequoz D., Burnier M., Niederberger M., Brunner H.R., Nussberger J., Waeber B.
ISSN
0305-1870
Statut éditorial
Publié
Date de publication
1994
Peer-reviewed
Oui
Volume
21
Numéro
2
Pages
93-100
Langue
anglais
Notes
Publication types: In Vitro ; Journal Article ; Research Support, Non-U.S. Gov't - Publication Status: ppublish
Résumé
1. The purpose of this study was to examine the contribution of the sympatho-adrenomedullary system to the blood pressure response to an intravenous bolus of thyrotropin-releasing hormone (TRH) in conscious medullectomized and sham-operated rats. 2. The peak pressor effect of 0.5 mg TRH was significantly increased in rats having no adrenal medulla (+24.2 +/- 1.6 mmHg, mean +/- s.e.m., P < 0.01) as compared to sham-operated animals (+12.2 +/- 3.0 mmHg). 3. Blockade of alpha-adrenergic receptors with phentolamine abolished the pressor effect of TRH in control rats (+2.1 +/- 1.9 mmHg) but did not attenuate the blood pressure response of medullectomized rats (+21.5 +/- 4.7 mmHg). In contrast, beta-blockade with propranolol blunted the blood pressure responsiveness of rats subjected to adrenal medullectomy (+12.4 +/- 2.6 mmHg) but did not modify the effect of TRH in sham-operated controls (+10.9 +/- 2.9 mmHg). 4. The direct in vitro effect of TRH on isolated mesenteric rat arteries was also evaluated. TRH did not induce contractions of isolated arteries. 5. These results suggest that in rats with intact adrenals, the pressor effect of intravenous TRH is mediated primarily by a stimulation of alpha-adrenergic receptors. Adrenal medullectomy appears to enhance the blood pressure response to intravenous TRH. Activation of cardiac beta-adrenoceptors seems to contribute to the blood pressure increasing effect of intravenous TRH in medullectomized animals.
Mots-clé
Acetylcholine, Adrenal Medulla, Animals, Blood Pressure, Heart Rate, Injections, Intravenous, Male, Mesenteric Arteries, Muscle, Smooth, Vascular, Norepinephrine, Phentolamine, Propranolol, Rats, Rats, Wistar, Sympathetic Nervous System, Thyrotropin-Releasing Hormone, Vasoconstriction
Pubmed
Web of science
Création de la notice
05/03/2008 16:41
Dernière modification de la notice
20/08/2019 13:10
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