Substance P - Definition and Overview

In neuroscience, Substance P is a neuropeptide: a short-chain polypeptide that functions as a neurotransmitter. It is especially involved in the transmission of pain impulses from peripheral receptors to the central nervous system (it derives its name from the first letter of pain). The endogenous receptors for Substance P belong to the tachykinin sub-family of GPCRs. The receptor with the greatest affinity for Substance P is called the Neurokinin 1 receptor.

Substance P is an 11-amino acid polypeptide with the sequence:

Arg Pro Lys Pro Gln Gln Phe Phe Gly Leu Met

It has been theorised that it plays a part in fibromyalgia. Capsaicin has been shown to reduce the levels of Substance P.

It has also been speculated that substance P is responsible for the burning "pain" sensation in the mouth while eating strong curried foods. Since the amount of substance P in the body can decrease over time, it has been theorized that this is the reason why frequent curry-eaters seem more comfortable eating spicy foods (including curry).

Naked Mole Rats lack Substance P and do not feel pain when painful stimuli are administered.