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Biomedical subjects

R Gryglewski

Publications and source records attributed to R Gryglewski.

53 records · Page 3Linked to original sources
PubMed1970

The inactivation of noradrenaline and isoprenaline in dogs.

1. The removal of infused noradrenaline and isoprenaline from the circulation of the dog has been studied, using the blood-bathed organ technique.2. Both catecholamines were removed in peripheral vascular beds; in all organs studied, noradrenaline was removed to a greater degree than isoprenaline.3. The hind legs removed an average of 60% of the noradrenaline passing through, but only 34% of the isoprenaline. With noradrenaline, the degree of removal decreased as the concentration increased, but with isoprenaline, the degree of removal increased with concentration.4. After phenoxybenzamine, the proportion of isoprenaline removed was unchanged, whereas that of noradrenaline was decreased. The change in removal with the concentration of noradrenaline was also abolished.5. The results are consistent with the concept that a small fraction of infused noradrenaline is removed from the circulation by Uptake(1) and that this is blocked by phenoxybenzamine. Isoprenaline, and the rest of the noradrenaline, are removed by another process (Uptake(2)?) followed by intracellular metabolism. This inactivation process is unaffected by phenoxybenzamine in concentrations sufficient to give alpha-adrenoceptor blockade.6. After isoprenaline infusions, a substance sometimes appeared in the circulation which contracted the blood-bathed organs.7. The systemic pressure response to vaso-active hormones is not a reliable indicator of the concentration of hormone in the arterial circulation.

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PubMedDate not supplied

Regulatory role of prostaglandins in the vascular system.

It is reported that noradrenaline-induced vasoconstriction initiates generation of prostaglandins of the E series by vasculas walls. These endogenous prostaglandins attenuate the vasoconstrictor effect of noradrenaline. Inhibitors of prostaglandin biosynthesis (indomethacin, mefenamic acid) abolish acute tolerance to noradrenaline infusions and counteract hypotension which is induced in cats by injection of endotoxin or by injection of rat blood.

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PubMedDate not supplied

The dual action of meclofenamate on the contractile response to PGF2 alpha in the guinea-pig trachea.

Indomethacin and meclofenamate (1 mug/ml) enhance contractile action of PGF2 alpha (5-20 mug) in guinea-pig tracheas superfused with Tyrode solution (5 ml/min). Unlike indomethacin, meclofenamate at a concentration of 10 mug/ml antagonizes contractions of guinea-pig tracheas produced by PGF2 alpha (5-20 mug), while the contractile action of histamine (0-5-2-0 mug) is enhanced. It is concluded that low concentrations of meclofenamate (1 mug/ml) inhibit prostaglandin biosynthesis in tracheal smooth muscles and therefore contractile action of exogenous PGF2 alpha is enhanced, while meclofenamate at a high concentration (10 mug/ml) blocks the receptor sites for PGF2 alpha.

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