Substance P: Difference between revisions

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==Receptor==

SP has high affinity for the Neurokinin 1 receptor (NK1), although it also activates NK2 and NK3. NK1 receptors are often located on neurons that also express [[norepinephrine]] or [[serotonin]] receptors, and is found in brain regions known to be involved in emotional responses, such as the hippocampus and amygdala.<ref name="mood" />

SP has high affinity for the Neurokinin 1 receptor (NK1), although it also activates NK2 and NK3. NK1 receptors are often located on neurons that also express [[norepinephrine]] or [[serotonin]] receptors and is found in brain regions known to be involved in emotional responses, such as the hippocampus and amygdala.<ref name="mood" />

===Function as a neurotransmitter or neuromodulator===

Substance P does not function like a typical neurotransmitter. There exists no SP transporter to pump the peptide back into the axon terminal, unlike neurotransmitters like dopamine or serotonin which have protein pumps that function to recycle the neurotransmitter once it has left the receptor. Instead, SP must be synthesized from scratch again. However, SP is believed to be released beyond the synapse, and may diffuse over larger distances than traditional neurotransmitters, which are limited to the [[synapse]], the tiny gap between one neuron on the sending end and one on the receiving one. Certain regions of the brain have many NK1 receptors but little Substance P or vice versa, which may have different explanations~~, but one~~ possible explanation is that SP may float over larger distances and subsist in the plasma surrounding cells for longer periods of time.

Substance P does not function like a typical neurotransmitter. There exists no SP transporter to pump the peptide back into the axon terminal, unlike neurotransmitters like [[dopamine]] or [[serotonin]] which have protein pumps that function to recycle the neurotransmitter once it has left the receptor. Instead, SP must be synthesized from scratch again. However, SP is believed to be released beyond the synapse and may diffuse over larger distances than traditional neurotransmitters, which are limited to the [[synapse]], the tiny gap between one neuron on the sending end and one on the receiving one. Certain regions of the brain have many NK1 receptors but little Substance P or vice versa, which may have different explanations. One possible explanation is that SP may float over larger distances and subsist in the plasma surrounding cells for longer periods of time.

==Role in pain perception and interaction with opioids==

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 ==Receptor==
-SP has high affinity for the Neurokinin 1 receptor (NK1), although it also activates NK2 and NK3. NK1 receptors are often located on neurons that also express [[norepinephrine]] or [[serotonin]] receptors, and is found in brain regions known to be involved in emotional responses, such as the hippocampus and amygdala.<ref name="mood" />
+SP has high affinity for the Neurokinin 1 receptor (NK1), although it also activates NK2 and NK3. NK1 receptors are often located on neurons that also express [[norepinephrine]] or [[serotonin]] receptors and is found in brain regions known to be involved in emotional responses, such as the hippocampus and amygdala.<ref name="mood" />
 ===Function as a neurotransmitter or neuromodulator===
-Substance P does not function like a typical neurotransmitter. There exists no SP transporter to pump the peptide back into the axon terminal, unlike neurotransmitters like dopamine or serotonin which have protein pumps that function to recycle the neurotransmitter once it has left the receptor. Instead, SP must be synthesized from scratch again. However, SP is believed to be released beyond the synapse, and may diffuse over larger distances than traditional neurotransmitters, which are limited to the [[synapse]], the tiny gap between one neuron on the sending end and one on the receiving one. Certain regions of the brain have many NK1 receptors but little Substance P or vice versa, which may have different explanations, but one possible explanation is that SP may float over larger distances and subsist in the plasma surrounding cells for longer periods of time.
+Substance P does not function like a typical neurotransmitter. There exists no SP transporter to pump the peptide back into the axon terminal, unlike neurotransmitters like [[dopamine]] or [[serotonin]] which have protein pumps that function to recycle the neurotransmitter once it has left the receptor. Instead, SP must be synthesized from scratch again. However, SP is believed to be released beyond the synapse and may diffuse over larger distances than traditional neurotransmitters, which are limited to the [[synapse]], the tiny gap between one neuron on the sending end and one on the receiving one. Certain regions of the brain have many NK1 receptors but little Substance P or vice versa, which may have different explanations. One possible explanation is that SP may float over larger distances and subsist in the plasma surrounding cells for longer periods of time.
 ==Role in pain perception and interaction with opioids==