Abstract
Beta adrenergic receptor blocking actions of D and L isomers of butoxamine, INPEA, MJ 1999, pronethalol and related agents were investigated in the isolated guinea-pig tracheal chain preparation. D(-)-Isoproterenol was used as the agonist and the tissue was exposed to the antagonists for 30 min. pA2 values for (±)-pronethalol, D(-)-butoxamine, D(-)-MJ 1999 and D(-)-INPEA were 7.26, 7.23, 6.79 and 6.50, respectively. The L(+)-isomers were less active. pA2 values for L(+)-pronethalol, L(+)-MJ 1999 and L(+)-INPEA were 5.18, 5.15 and 4.22, respectively. Desoxy MJ 1999 (pA2, 3.88) appeared to be less active than L(+)-MJ 1999. L(+)-Butoxamlne and (±)-pseudobutoxamine did not produce any beta adrenergic blockade. Only D(-)-ephedrine produced significant blockade of beta adrenergic receptors; other isomers of ephedrine were inactive. Steric structure-action relationship is discussed.
Footnotes
- Received October 12, 1967.
- Accepted December 8, 1967.
- © 1968 by The Williams & Wilkins Company
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