Some examples of the effect of asymmetric nitrogen atoms on physiological activity / by P.P. Laidlaw.

  • Laidlaw, Patrick Playfair, 1881-1940.
Date:
[1913]
Catalogue details

Licence: In copyright

Credit: Some examples of the effect of asymmetric nitrogen atoms on physiological activity / by P.P. Laidlaw. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    Some experiments were performed by perfusing Ringer’s solu- tion through a paralysed or partially paralysed limb, until re- covery was about complete; but it was found that, when once a muscle had been poisoned by one isomer, it never recovered completely within the rather narrow time limits of a perfusion experiment; so that it remained more susceptible to the same, or opposite isomer, and paralysis could be easily obtained with weaker dilutions than that originally needed. This method was, therefore, abandoned and a comparison of one limb, one isomer, against opposite limb, opposite isomer, was adopted. Fig. 1. Effect of 1 in 20,000 a Tetrahydroberberine Methochloride Figure 1 is a typical tracing of the effect of 1 in 20,000 a tetrahy- droberberine methochloride; and figure 2 that of 1 in 20,000 0 tetrahydroberberine methochloride. It will be observed that the a compound is much weaker than the /3. By comparing weaker strengths of /3 tetrahydroberberine methochloride with 1 in 20,000 a on other frogs it was found that 1 in 80,000 produced approximately an equal effect. Figure 3 is a chart representation of two experiments. The ordinates represent the height of gastrocnemius contractions, the abscissa time in minutes of perfusion with the drug. The records with 1 in 50,000 a racemic canadine methochloride and 1 in