This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Physiology
Which neurotransmitter is responsible for anterograde dilatation of the small intestine? 
Select and explain. 
A. image_question, B. image_question, C. image_question, D. image_question
A: image_question
Answer: A: image_question 
Explanation: 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