Fig. 3.
The effects of 5-hydroxytryptamine (HT), histamine (H), and acetylcholine (ACh) on the fundal strip before and after hyoscine hydrobromide. (a), Contractions produced by 3 μg. histamine, 2 ng. HT and 23 ng. acetylcholine. Hyoscine was added to the Ringer to give a final concentration of 10−7 (6), Shows that sensitivity to acetylcholine is greatly reduced; 3 μg. acetylcholine and 18 μg. histamine now have to be used. The response to 2 ng. HT is slightly larger than before. Scale and time as in Fig. 2.