Which neurotransmitter is responsible for anterograde dilatation of the small intestine?

VIP is responsible for antergrade dilatation of the small intestine. Cholinergic neurons passing inn antegrade direction produce NO and VIP which cause relaxation of a segment of the intestine in front of the bolus. Cholinergic neurons passing in retrograde direction produce substance P and acetylcholine which cause contraction of a segment of the intestine behind the bolus. Ref: Ganong&;s Review of Medical Physiology 26th edition Pgno: 485