<prompt> In peripheral tissues which of the following contains substance PPlasma cellMast cellNerve terminalVascular endothelium  <response>: Substance P SP is an undecapeptide a peptide composed of a chain of 11 amino acid residues member of the tachykinin neuropeptide family. It is a neuropeptide, acting as a neurotransmitter and as a neuromodulator. Ref guyton and hall textbook of medical physiology 12e pg 83 