[Acute tolerance to noradrenaline ("noradrenaline escape")].
The decline in arterial systemic blood pressure which follows the initial rise during i.v. perfusion of L-noradrenaline in normal rats has been compared with the same type of decline induced by metaraminol or phenylephrine, both alpha-sympathomimetic drugs (acute tolerance or escape). Vasoconstrictor activity of noradrenaline in shot i.v. injection is regularly decreased when acute tolerance develops. This hyposensitivity to NA indicates that a change in alpha-receptor affinity for circulating NA may explain the acute tolerance as well as the noradrenaline escape.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D004361:Drug Tolerance; D008680:Metaraminol / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology*; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats
D010656:Phenylephrine; D008680:Metaraminol; D009638:Norepinephrine
Sur la tolérance aiguë à la noradrénaline ("noradrenaline escape").