Endoluminal Substance P is Released by a Meal

Substance P (SP) has been identified within the lumen of the gastrointestinal tract. We have previously demonstrated that electrical stimulation releases SP from the guinea pig myenteric plexus[1]. Vagal stimulation releases SP into the lumen of the feline upper small intestine[2]. The possible physiological role of endoluminal SP remains unclear. The purpose of this study was to investigate if a physiologic stimulus, a high protein meal, provokes the intraluminal release of SP and whether the release is under cholinergic and/or adrenergic control.