Substance P, actions are all except: (A) Vasoconstriction, (B) Pain transmission, (C) Axon reflex, (D) Peristalsis
Answer is A. Substance P saw at

Primary pain nerve endings in the dorsal horn of the spinal cord
Hypothalamus
Nigrostriatal pathway of basal ganglia

It is probably involved in pain transmission, axon reflex and peristalsis.