Contribution to the Study of Veratrine Contraction, with Special Reference to the Action of Quinine.

In this investigation, the veratrine contraction was studied with special reference to the action of quinine, and from the results obtained, the following summary and conclusion are made1. Various forms of veratrine contraction were found to be different representations of twitch and veratrine components, corresponding to the concentration of the drug, duration of the action of the drug (time factor), intensity and frequency of stimulations and individual sensitivity of muscles. 2. Veratrine-like contractions were evoked by glycerine and formaldehyde. 3. Veratrine contraction was obviated by lowering the temperature and facilitated by raising it. An intimate relations between the effective minimal dosis of veratrine and temperature were noted. 4. Veratrine contraction was depressed or abolished by calcium or potassium chlorides. Relations between threshold concentration of veratrine and calcium or potassium chlorides were determined. 5. Acidity inhibited the occurrence of veratrine contraction, alkalinity facilitated it. 6. Height of contraction of veratrinised muscle was higher than normal muscle, in twitch as welt as in tetanus. Refractory period of veratrine muscle was greatly prolonged and found in the descending phase of veratrine contraction. 7. Quinine obviated veratrine contraction. Veratrine-quinine equilibrium ratio was determined. 8. Atropine inhibited the action of veratrine on muscle. 9. Ergotoxine retarded or depressed the occurrence of veratrine contraction, when applied previously, while if applied afterwards, it exaggerated at first, then alleviated gradually veratrine contraction. 10. Acetylcholine had no effect on veratrine contraction. Eserine, like atropine, inhibited veratrine contraction. 11. Adrenaline caused complete dissociation of twitch and veratrine components. 12. Monoiodoacetic acid had no effect on the occurrence of veratrine contraction. 13. Veratrine had no effect on isolated frog's heart. 14. Veratrine caused increased tonicity and irregular tonic contraction on non-striated muscles (dorsal muscle of leech, intestine and uterus of guinea-pig).