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DURATIONS OF RESPONSES TO ADRENALINE, TYRAMINE, AND EPHEDRINE
Author(s) -
Clark A. J.,
Raventos J.
Publication year - 1939
Publication title -
quarterly journal of experimental physiology and cognate medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0033-5541
DOI - 10.1113/expphysiol.1939.sp000803
Subject(s) - tyramine , chemistry , ephedrine , epinephrine , blood pressure , duration (music) , anesthesia , medicine , endocrinology , biochemistry , art , literature
1. The relation between concentration and duration of action of adrenaline acting on the frog's auricle wetted with a small amount of solution indicates that the adrenaline is oxidised by a tissue catalyst. The rate of destruction varies as the concentration and the time of half oxidation is about 60 secs. 2. A comparison of the dosage‐duration curves obtained in the cat with adrenaline before and after pyrogallol and with ephedrine indicates that the duration is limited by two mechanisms, namely, oxidation and, in addition, some other mechanism which does not depend on the lability of the drug. 3. The relation between dosage of adrenaline (below 3 µg./kg.) and the duration of action on the cat's blood‐pressure and nictitating membrane and gut indicates that the amount of adrenaline destroyed per unit of time varies as the concentration and that half‐destruction occurs in the tissues in about 20 secs. 4. When the dosage of adrenaline exceeds 3 µg./ kg. the amount destroyed is between 0·1 and 0·2, Lg./ µg/kg. per sec., and this amount does not change when the dosage is increased. 5. The curves relating the concentration (or dosage) and the duration of action of tyramine on the wetted frog's auricle and on the cat's blood‐pressure are similar in shape to those obtained with adrenaline. Tyramine is inactivated about five times more rapidly than is adrenaline. The expenses of this research were defrayed by a grant from the Moray Research Fund of Edinburgh University, and one of the authors (J. R.) is in receipt of a grant from Messrs. Imperial Chemical Industries, Ltd. We desire to express our thanks for this help.