Overview
Substance P is an 11-amino acid neuropeptide belonging to the tachykinin family, functioning as a key neurotransmitter and neuromodulator involved in pain signal transmission, inflammation, and the gut-brain axis. It is produced by primary afferent neurons, the central nervous system, and immune cells. While primarily known for its role in pain signaling (NK1 receptor activation), substance P also regulates neurogenesis, wound healing, and immune modulation, leading to research into both NK1 antagonists (for pain and nausea) and substance P agonism (for wound healing and hair growth).
Mechanism of Action
Substance P binds neurokinin 1 (NK1) receptors, which are GPCRs activating phospholipase C via Gq/11, driving IP3 and DAG second messengers, Ca2+ mobilization, and PKC activation. In the dorsal horn of the spinal cord, this amplifies pain signals transmitted by nociceptors (central sensitization). Peripherally, it triggers neurogenic inflammation through vasodilation, increased vascular permeability, and mast cell degranulation. In wound healing contexts, substance P promotes keratinocyte migration and proliferation, angiogenesis, and stem cell mobilization.
Potential Benefits
- Neurotransmitter in pain pathways (research for NK1 antagonist development)
- Neurogenic inflammation modulation
- Wound healing promotion via keratinocyte and stem cell effects
- Potential hair follicle activation via NK1 receptor in follicles
- Neurogenesis promotion in some brain regions
- Antimicrobial activity at high concentrations
Research Dosage Notes
The following reflects doses used in published research studies. This is not medical advice.
Research tool primarily. NK1 antagonists (aprepitant) used clinically.
Amino Acid Sequence
Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH2 (RPKPQQFFGLM-NH2)
Side Effects & Safety
- Promotes pain sensitization at pathological concentrations
- Neurogenic inflammation
- Vasodilation and flushing
Synergistic Compounds
The following compounds have been studied alongside Substance P for potential complementary or synergistic effects: