Definition of substance P
: a neuropeptide that consists of 11 amino acid residues, that is present in the nervous system and gastrointestinal tract, that causes the contraction of smooth muscle and dilation of blood vessels, and that acts as a potent neurotransmitter especially in the transmission of signals from pain receptors
First Known Use of substance p
Medical Definition of substance P
: a neuropeptide that consists of 11 amino acid residues, that is widely distributed in the brain, spinal cord, and peripheral nervous system, and that acts across nerve synapses to produce prolonged postsynaptic excitation
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