THE ACTION OF LUPINE ALKALOIDS ON THE MOTILITY OF THE ISOLATED RABBIT UTERUS

¹ From the Department of Pharmacology, George Washington University School of Medicine, Washington, D. C.

1. A study of sparteine sulfate USP IX, and samples of sparteine disulfate, d-lupanine dihydrochloride, trilupine and lupinine base on the motility of isolated rabbit uterus showed that with effective concentrations there was stimulation of amplitude, rate, or tone, or a combination of these, followed in some higher concentrations by depression of amplitude or rate, with or without decrease in tone towards original level.

2. Return to previous level of activity could be obtained in Locke-Ringer's solution after any of these drugs in the concentrations used (up to 1:1,000).

3. The qualitative effects of these alkaloids upon motility of the isolated rabbit uterus were quite similar in the virgin, rutting and pregnant types, but the magnitude of response was greatest in the pregnant and least in the virgin type. The pregnant, and less so the rutting type, showed a stronger tendency toward increases in tonus with the higher concentrations.

4. Little or no difference was found between the activity of sparteine sulfate USP IX and sparteine disulfate, laboratory sample.

5. Sparteine disulfate 1:100,000 was the minimal concentration producing stimulation; 1:50,000 or 1:20,000 produced maximal, maintained stimulation; 1:20,000 or 1:5,000, stimulation not maintained at maximal level more than several minutes; and 1:5,000 or 1:1,000 produced stimulation followed almost immediately by depression of amplitude even to cessation of motility.

6. Trilupine base and d-lupanine dihydrochloride produced effects qualitatively similar to those produced by sparteine disulfate, but were only about 1/15 as effective. No depressant effects were observed. Lupinine base was only about 1/5 as effective a stimulant as sparteine disulfate; however, the increase in tone was greater, and in high concentrations (1:5,000 or 1:1,000) it tended to produce prolonged spasticity.

7. Comparison of the results of this study with studies on comparative toxicities, indicate that, if used clinically as ecbolics, sparteine sulfate would probably be the safest, trilupine base about , lupinine base about 1/5, and d-lupanine dihydrochloride only about 1/5 as safe as sparteine disulfate.