![Dynorphins Structure](/CAS/20180906/GIF/74913-18-1.gif)
Dynorphins
- Product NameDynorphins
- CAS74913-18-1
- MFC99H155N31O23
- MW2147.4839
- EINECS
- MOL File74913-18-1.mol
Usage And Synthesis
Both Dyn and αNE are heptapeptide sequences that
contain Leu-ENK (Tyr-Gly-Gly-Phe-Leu) in their
N-termini. Isolation of these peptides from the porcine
pituitary and hypothalamus was first reported in 1979.
Dyn A, Dyn B, and αNE are generated from a common
precursor prodynorphin (PDYN, also known as
proenkephalin-B, PENK-B) by proteolytic cleavage.
Human PDYN contains three copies of Leu-ENK, which
are flanked by dibasic amino acid residues. Other mammalian PDYN has a similar structure. In amphibians and
fishes such as lungfish and shark, PDYN contains two
copies of ENKs, Leu-ENK or Met-ENK, in addition to
Dyn A, Dyn B, and αNE. Teleost PDYN also contains five
ENKs, although two of them are unusual; one is present
as a relic sequence and the other is Tyr-Gly-Gly-Phe-Ile.
Thus, PDYN in the common ancestor may also have
had five copies of ENKs. Several peptides with differential length are produced
from PDYN.
![Dyn A, Dyn B, and αNE Dyn A, Dyn B, and αNE](/NewsImg/2022-06-09/6379036269531832998023439.jpg)
![Several peptides with differential length Several peptides with differential length](/NewsImg/2022-06-09/6379036274818635387088016.jpg)
![Dyn A, Dyn B, and αNE Dyn A, Dyn B, and αNE](/NewsImg/2022-06-09/6379036269531832998023439.jpg)
![Several peptides with differential length Several peptides with differential length](/NewsImg/2022-06-09/6379036274818635387088016.jpg)
The human PDYN gene, PDYN, location 20p13, consists
of four exons. Four cAMP responsive element (CRE)-like
sites (DYNCRE1, 2, 3, and 4) are important for PDYN
expression, and an AP-1 site, representing a specific target
for Jun/Fos, and an SP-1-like domain, targeted by NGFI-A
and a single AP-2 consensus site, have been proposed as
promoter elements. Human PDYN contains 254 aa residues and comprises a signal peptide of 20 aa residue followed by a cysteine-containingN-terminal sequence and
a region containing the repeated ENK sequences.
In the rat, the level of Pdyn mRNA expression has been
shown to increase in the hypothalamus in response to
osmotic challenge. In addition, seven daily injections
of a dopamine agonist, apomorphine, caused an increase
in the level of Pdyn mRNA expression in the striatum. Electrical stimulation in vivo decreased the expression
of Pdyn mRNA in the dentate gyrus in the hippocampus.
PDYN-derived peptides such as Dyn and αNE are agonists for KOR (also known as κ receptor, KOR-1, OP2, etc.),
which is a subtype of opioid receptors belonging to the
G protein-coupled receptor superfamily. Human KOR is
located on chromosome 8 (8q11.2). Dyn-A (1–17) is considered to be an endogenous ligand for KOR.
Nalfurafine, ethylketocyclazocine, hydromorphone,
nalbuphine, morphine, fentanyl, etc., are agonists for
human KOR. Buprenorphine, nalmefene, naltrexone, naloxone, alvimopan, etc., are antagonists for human KOR.
Based on the localization of KOR expression, dynorphins are involved in learning and memory, emotional
control, stress response, and pain. Administration of
high-efficacy KOR agonist caused depressant-like effects
and anhedonia in rodents. Absence of KOR does not modify expression of the
other components of the opioid system, and behavioral
tests indicate that spontaneous activity is not affected
in mutant mice. KOR is implicated in the perception of
visceral chemical pain. KOR is critical for mediating the
hypolocomotor, analgesic, and aversive actions of a
KOR agonist. This receptor does not contribute to morphine analgesia and reward, but participates in the
expression of morphine abstinence.
Acute alcohol intoxication stimulates the release of
Dyn. Dyn/KOR systems contribute to the negativereinforcing effects of alcohol based on the prodepressive
effects of Dyn/KOR system activation, the antidepressant properties of KOR antagonists, and the involvement
of KOR with the dysphoria produced by stress. The
Dyn/KOR system is related to the pathogenesis and
pathophysiology of several psychiatric disorders. Dyn/
KOR systems are recruited by various stimuli and act
to shape neuronal activity, alter presynaptic neurotransmitter release, and decrease neuronal excitability.
Changes in this system may contribute to symptom clusters that are shared by various psychiatric disorders.
Dynorphin is an extraordinarily potent opioid peptide. To
denote its powerful potency, the peptide was named
“dynorphin” (“dyn” from the Greek dynamis=power and
“orphin” for endogenous morphine peptide). α-Neoendorphin has been identified as a “big” leucine enkephalin
(Leu-ENK) with potent opiate activity.
Hydromorphone, morphine, fentanyl, etc., are used to
treat moderate to severe pain. The antagonist buprenorphine is used to treat severe pain, and to ameliorate opioid dependence. Naltrexone is used alongside behavioral
therapy both for opiate addiction and for alcohol dependency. Naloxone is used to reverse narcotic depression.
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