Which statement is true about Substance P?

Which statement is true about Substance P?

• A. It inhibits pain signals
• B. It is a peptide neurotransmitter associated with pain facilitation
• C. It is the primary inhibitory neurotransmitter in the brain
• D. It is produced by astrocytes exclusively

Answer: (B)

Substance P is a peptide neurotransmitter that facilitates pain signaling. It is released from nociceptive neurons in response to tissue damage and enhances the transmission of pain by acting on NK1 receptors in the spinal cord and brain, contributing to increased excitability of pain pathways and central sensitization. This excitatory role explains why it is linked to pain perception and inflammatory responses. It is not an inhibitory transmitter—those roles are carried by chemicals like GABA and glycine. It is produced by neurons, especially those in the dorsal root ganglia and dorsal horn, not exclusively by astrocytes. Therefore, Substance P is a peptide neurotransmitter associated with pain facilitation.

Substance P is a peptide neurotransmitter that facilitates pain signaling. It is released from nociceptive neurons in response to tissue damage and enhances the transmission of pain by acting on NK1 receptors in the spinal cord and brain, contributing to increased excitability of pain pathways and central sensitization. This excitatory role explains why it is linked to pain perception and inflammatory responses. It is not an inhibitory transmitter—those roles are carried by chemicals like GABA and glycine. It is produced by neurons, especially those in the dorsal root ganglia and dorsal horn, not exclusively by astrocytes. Therefore, Substance P is a peptide neurotransmitter associated with pain facilitation.