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Substance P (SP) & Endorphin
Content
• Neuropeptides & pain perception– Substance P– endorphins
• NK1-receptor & Central opiate receptors• Endorphins• Enkephanlin
Substance P (SP)•a kind of neuropeptide (belongs to the tachykinin neuropeptide family)•Mainly found in the brain and spinal cord•Substance P is an important element in pain perception
tachykinin family• tachykinin family : Phe-X-Gly-Leu-Met-
NH2 X is either an Aromatic( 苯環類 )
or an Aliphatic amino acid( 酯胺酸 )
Substance P
NK1-receptor
• The endogenous receptor for Substance P is neurokinin 1 receptor (NK1-receptor, NK1R).
• NK1-receptor belongs to the tachykinin receptor sub-family of GPCRs(G-protein couple receptor)
• NK1-receptor is considered an attractive drug target, particularly with regards to potential analgesics and anti-depressants
Tachykinin peptides Substance p
Mammalian tachykinin receptor NK-1 (most attractive)
NK-2
NK-3
……
….
Function of Substance P
• SP has been associated with the regulation ofmood disorders, anxiety, stress , etc.
• SP also relates to Neurogenic inflammation• Substance P receptor(NK1-receptor)
antagonists may have important therapeutic applications in the treatment of a variety of stress-related illnesses, in addition to their potential as analgesics
Other application• Cell growth : Substance P has been known to
stimulate cell growth in culture, and it was shown that Substance P could promote wound healing of non-healing ulcers in humans
• Diabetes : Substance P has also been shown to reverse diabetes in mice but effects to insulin secretion seems to be species dependent.
• Vasodilation : It has been shown that vasodilatation to substance P is dependent on the NK1 receptor located on the endothelium.
• Why may a runner who twists his leg during a competition finish the run before he really feels the pain?
Central opiate receptors
• The endogenous analgesia system is a pain control system descending from brainstem to the spinal cord.
• Endogenous opioids are substances with opiate-like effects.
• occurring in the nervous system – ß -endorphin,met-enkephalin, leu-enkephalin,
dynorphin and many others
• Endogenous opioids are derivatives of three large protein molecules encoded by three different genes. – e.g.
ACTHPOMC ß -endorphin
Nerve impulse Spinal cord Endorphins
( - ):releasing pain signals
Stimulation or increased tone of the analgesia system can suppress strong pain signals entering the spinal cord through the dorsal spinal horn.
背部
腹部
Endorphin
• endogenous opioid neuropeptides • function as neurotransmitters• produced by the pituitary gland and the
hypothalamus • during exercise,excitement, pain, consumption
of spicy food, love and orgasm,• resemble the opiates in their abilities to
produce analgesia and a feeling of well-being
“endo-”
morphineendogenous
“–orphin”
Enkephalin
• An enkephalin is a pentapeptide involved in regulating nociception in the body.
Met-enkephalin
• The enkephalins are termed endogenous ligands, or specifically endorphins
• they are internally derived and bind to the body's opioid receptors.
– Met-enkephalin is Tyr-Gly-Gly-Phe-Met.– Leu-enkephalin has Tyr-Gly-Gly-Phe-Leu.
資料來源:• http://en.wikipedia.org/wiki/Beta-endorphin• http://en.wikipedia.org/wiki/Substance_P• http://en.wikipedia.org/wiki/Brainstem• http://tw.knowledge.yahoo.com/question/question?
qid=1405111805839• http://tw.knowledge.yahoo.com/question/question?
qid=1005010501521• Campbell biology campbell reece 8th edition by Reece,
Campbell 2007 •