PHARMACOLOGICAL ACTIONS OF QUATERNARY AMMONIUM SALTS

¹ The Department of Pharmacology, University of Edinburgh

1. The author measured the actions of various quaternary ammonium salts on a series of isolated tissues, namely: leech muscle, frog's rectus abdominis, frog's auricle, and rat's gut.

2. The following series of compounds were tested:—

(1) Me₃N.Me, Me₃N.Et . . . Me₃N.Oct, Me₃N.Cet.

(2) Me₄N to Bu₄N.

(3) Me₄N, Me₃.EtN, Me₂.Et₂N, Me.Et₃N, Et₄N.

(4) Me₃N.Phen, Me₃N.Benz, Me₃N(CH₂)2Phen.

3. The tissues studied fell into three groups as regards their responses to the Me₃N.R series:

Group A. Leech muscle, which resembled in its response the motor-nerve endings.

Group B. The rectus abdominis.

Group C. The frog's auricle and the rat's gut.

In Group A all the compounds produced actions similar in kind but of varying intensity.

In Group C a reversal of action occurred. An increase of R in the Me₃N.R series caused increased activity up to Me₃N.Am, but further increase abolished the action, and the higher compounds then inhibited the action of the lower members of the series.

The responses of the rectus abdominis were intermediate in character between Groups A and C, but more nearly resembled those of Group C.

4. The responses to the series Me₄N, Et₄N, Br₄N, and But₄N showed a similar grouping, but the similarity between the leech response and the curariform action was less complete.

5. The series Me₄N, Me₃EtN, Me₂Et₂N, etc., showed more complex responses.

6. The compound Me₃N.CHPhen resembled in its actions Me3BuN and not Me3OctN. Hence the effect of introducing a phenyl group resembled that of the addition of 3 carbon atoms in a straight chain rather than that of the addition of 6 carbon atoms.

It is with pleasure that I put in record my indebtedness to Prof. A. J. Clark for his kind hospitality, and for his constant help and advice. The expenses of this research were in part defrayed by the Moray Fund, for which help I express my thanks.