J Physiol. 1954 Feb 26;123(2):277-88. doi: 10.1113/jphysiol.1954.sp005050.
The effect of intraluminal application of 5-hydroxytryptamine and 5-hydroxytryptophan on peristalsis; the local production of 5-HT and its release in relation to intraluminal pressure and propulsive activity.