Substance P

• Substance P is an undecapeptide belonging to the tachykinin neuropeptide family. It functions as a neurotransmitter and neuromodulator.
• Substance P: Acts on NK1 receptors in CNS and peripheral tissues.

Synthesis:

• Neurons: Primarily synthesized in the central and peripheral nervous systems.
• Release: Released from sensory nerve endings in response to pain and inflammation.

Functions of Substance P:

• Neurotransmission: Transmits pain signals from peripheral nerves to the central nervous system.
• Vasodilation and Increased Permeability: Contributes to inflammatory responses by acting on blood vessels.
• Immune Modulation: Influences immune cell activity and cytokine release.
• Smooth Muscle Contraction: Affects gastrointestinal and respiratory tract motility.

Receptors:

1. Neurokinin-1 (NK1) Receptors: High affinity for substances P; involved in pain transmission and inflammatory responses.
2. Neurokinin-2 (NK2) and Neurokinin-3 (NK3) Receptors: Bind substances P with lower affinity; have distinct physiological roles.

Clinical Relevance:

• Pain Management: NK1 receptor antagonists are explored for treating chronic pain and depression.
• Emesis Control: NK1 antagonists like aprepitant are used to prevent chemotherapy-induced nausea and vomiting.
• Inflammatory Diseases: Potential targets for treating conditions like asthma and arthritis.

Thank you for reading from Firsthope's notes, don't forget to check YouTube videos!