Substance P

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Chemical structure of Substance P

Substance P is a neuropeptide that functions as a neurotransmitter and neuromodulator. It is composed of 11 amino acids and is a member of the tachykinin neuropeptide family. Substance P is involved in the transmission of pain information into the central nervous system.

Structure

Substance P is a polypeptide consisting of a chain of 11 amino acids. Its sequence is Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met. The molecular weight of Substance P is approximately 1347.63 g/mol. The chemical structure of Substance P allows it to bind to the neurokinin-1 receptor (NK1 receptor), which is its primary receptor.

Function

Substance P is primarily associated with the pain pathway. It is released from the terminals of specific sensory nerves and is involved in the neurotransmission of pain and other sensory signals. Substance P is also involved in the regulation of mood disorders, anxiety, stress, nausea, and vomiting.

Pain Transmission

In the context of pain, Substance P is released from the terminals of afferent neurons in the dorsal horn of the spinal cord. It binds to the NK1 receptor on postsynaptic neurons, leading to the transmission of pain signals to the brain. This process is crucial for the perception of pain.

Other Functions

Substance P also plays a role in the inflammatory response and is involved in the regulation of the immune system. It can influence the vasodilation and vascular permeability of blood vessels, contributing to the inflammatory process.

Clinical Significance

Substance P has been implicated in various clinical conditions, including chronic pain, arthritis, fibromyalgia, and depression. Antagonists of the NK1 receptor, which block the action of Substance P, are being studied for their potential therapeutic effects in these conditions.

Related Pages

• Neuropeptide
• Neurotransmitter
• Pain
• Neurokinin-1 receptor
• Inflammation