Substance P is a tachykinin and physiologically acts as a neurotransmitter and neuromodulator in the nervous system. Pathologically, it can also trigger malignant cells to release cytokines and increase cell proliferation rates.
Definition: Substance P is the predominant neuropeptide released at primary afferent-second order neuron sysnapses upon high-intensity stimulation of nociceptive afferents. Via activation of NK1 receptors (see table in chapter nociception) substance P produces slow, long-lasting depolarisations of second order neurons . This leads to potentiation of the post-synaptic response to nociceptor stimulation and thereby functions as an intensity-coding mechanism for nociceptive transmission.
Functions as a neurotransmitter and is a key player in inflammation. It stimulates mast cell degranulation and histamine release and may amplify subsequent inflammatory responses causing a cascade effect that re-triggers the mast cells.
A protein neurotransmitter that is primarily involved in pain transmission. It is one of the most potent compounds affecting smooth muscle that causes dilation of blood vessels and contraction of the intestines and is thus presumed to play a role in inflammation.
An 11-amino acid peptide that is believed to be important as a neurotransmitter in the pain fiber system. This substance may also be important in eliciting local tissue reactions resembling inflammation.
In neuroscience, Substance P is a neuropeptide: a short-chain polypeptide that functions as a neurotransmitter and as a neuromodulator. It belongs to the tachykinin neuropeptide family.
