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At least 19 recordsLinked to original sources
PubMed1960

The effect of precursors of noradrenalin on the response to tyramine and sympathetic stimulation.

Previous observations have shown that the effects of sympathetic stimulation and of tyramine were absent in the organs of animals treated with reserpine, but that they were restored by an infusion of noradrenaline. Observations are described showing that an infusion of adrenaline did not restore the pressor action of tyramine in the cat or in the rat, but that in the rat the pressor action was restored by an infusion of dopamine, or of (-)-dopa, or of m-tyrosine,or of phenylalanine. Observations are also described showing that the effect of postganglionic stimulation of the fibres to the nictitating membrane and to the iris was restored by an infusion of dopamine or of (-)-dopa; it was restored less well by an infusion of noradrenaline. An infusion of noradrenaline did not restore the action of tyramine on the denervated iris or on the denervated vessels of the cat's foreleg. An infusion of noradrenaline appeared to increase the effect of sympathetic stimulation of the hypogastric nerves to the uterus of the virgin cat about as much as an infusion of adrenaline. An infusion of noradrenaline restored the constrictor action of nicotine on the perfused vessels of the rabbit ear.

Animals↗
PubMed1961

The effect of adrenaline, noradrenaline and isoprenaline on the guinea-pig uterus.

The actions of adrenaline, noradrenaline and isoprenaline were compared on the isolated guinea-pig uterus. In uteri from immature animals (200 to 350 g) adrenaline caused relaxation which changed to a biphasic effect and finally to a contraction in the course of an experiment (6 to 8 hr). Noradrenaline always caused contraction and isoprenaline relaxation. In uteri from oestrogen-treated animals adrenaline and noradrenaline caused contraction and isoprenaline caused relaxation. Isoprenaline potentiated the contraction produced by adrenaline and reversed the adrenaline relaxation to a contraction. The change of the pharmacological action of adrenaline was not related to the Na(+) and K(+) content of the uterus, which remained constant throughout an experiment involving repeated application of the amines. Nor could it be related to a change in the glycogenolytic effect of adrenaline estimated by determinations of total glycogen of the muscle which, however, may not reflect a momentary change in rate of breakdown.

Amines↗
PubMed1961

Effect of dopamine on the isolated perfused lung lobes of the dog.

Dopamine (beta-3:4-dihydroxyphenylethylamine) has a pressor action on the pulmonary vascular bed in isolated perfused lung lobes of the dog. Its pulmonary vasoconstrictor effect in this preparation is about 1/20-1/30 that of adrenaline or noradrenaline. When compared with adrenaline, dopamine is less effective as a vasoconstrictor in the bronchial vascular system than in the pulmonary circulation. Even very large doses of dopamine had no bronchomotor effect in the isolated perfused lung lobes. Addition of dopamine alone, or of dopamine together with some "new" blood, sometimes caused a potentiation of the pulmonary vasoconstrictor responses to sympathetic nerve stimulation.

Animals↗
PubMed1961

Potentiation of inhibitory and excitatory effects of catechol amines by bretylium.

Enhancement of both excitatory and inhibitory responses to adrenaline, noradrenaline and isoprenaline was demonstrated with bretylium both in vivo and in vitro. Excitatory responses studied included rise of blood pressure and contraction of the nictitating membrane in cats and the contraction of aortic strip in rabbits; the inhibitory responses studied were fall of cat blood pressure and relaxation of rat uterus and rabbit tracheal chain. Possible mechanisms of potentiation of the effects of catechol amines by bretylium are discussed. A sensitization of the peripheral effector cells is suggested as a likely mechanism of potentiation.

Amines↗