Ultradian variations in sensitivity of rat aorta rings to noradrenaline

The in vitro sensitivity of the rat aorta to the vasoconstrictor effect of noradrenaline was found to vary according to the time the animals were killed, with a minimum at 10:00 h and a maximum at 16:00 h. This ultradian rhythm was not influenced by the presence of the endothelium but was modified b...

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Bibliographic Details
Published inEuropean journal of pharmacology Vol. 229; no. 1; p. 69
Main Authors Gohar, M, Daleau, P, Atkinson, J, Gargouil, Y M
Format Journal Article
LanguageEnglish
Published Netherlands 08.12.1992
Subjects
Animals
Aorta, Thoracic - drug effects
Aorta, Thoracic - physiology
Circadian Rhythm - physiology
Endothelium, Vascular - physiology
In Vitro Techniques
Male
Norepinephrine - pharmacology
Rats
Rats, Wistar
Receptors, Adrenergic, beta - physiology
Vasoconstriction - drug effects
Vasoconstriction - physiology
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Summary:The in vitro sensitivity of the rat aorta to the vasoconstrictor effect of noradrenaline was found to vary according to the time the animals were killed, with a minimum at 10:00 h and a maximum at 16:00 h. This ultradian rhythm was not influenced by the presence of the endothelium but was modified by some, as yet unidentified, circulating factor(s). The results also strongly suggested an ultradian rhythm of in vitro sensitivity to the beta-adrenoceptor agonists, salbutamol and isoprenaline. This rhythm appears to be opposite to that for the sensitivity of aortic alpha-adrenoceptors to stimulation. In conclusion, our results demonstrate that the regulation of aortic tone follows an ultradian rhythm.
ISSN:0014-2999
DOI:10.1016/0014-2999(92)90287-E