1. Bovine dorsal root, dorsal half of its spinal cord or guinea-pig's whole brain was extracted with about 70% ethanol at room temperature. When the extract was incubated with trypsin after concentrated in vacuo, substance P (SP) present in the original extract was destroyed but gut-stimulating activity apparently still remains, which could be ascribed to a new component (CT).
2. CT could be extracted by the procedure quite similar to ROCHA e SILVA's extraction method of crude bradykinin and seemed to be of polypeptide nature.
3. The gut-stimulating activity of CT on guinea-pig ileum was barely affected by atropine, tryptamine, cocain, tetramethylammonium, hexamethonium, morphin, GABA and ε-amino-n-caproic acid and so resembles to that of SP. But contraction produced by the former is slower, not abolished by previous administration of SP, nor potentiated by LSD, but depressed by high dose of pyribenzamine.
4. Using guinea-pig's ileum, hen's rectal caeceum, and rat's uterus and colon, it was proved that action of CT is rather similar to that of plasma kinin and different from that of substance P.
5. It was found that the higher the SP content of the tissue, the more CT was obtained on incubation with trypsin, dorsal spinal cord and small intestine giving higher CT activity, skeletal muscle and ventral cord lower one.