Big dynorphin is an

endogenous opioid Opioid peptides or opiate peptides are peptides that bind to opioid receptors in the brain; opiates and opioids mimic the effect of these peptides. Such peptides may be produced by the body itself, for example endorphins. The effects of these p ...

peptide of the

dynorphin Dynorphins (Dyn) are a class of opioid peptides that arise from the precursor protein prodynorphin. When prodynorphin is cleaved during processing by proprotein convertase 2 (PC2), multiple active peptides are released: dynorphin A, dynorphin ...

family that is composed of both

dynorphin A Dynorphin A is a dynorphin, an endogenous opioid peptide that activates the κ-opioid receptor. Its amino acid sequence is Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys, a tridecapeptide. Dynorphin A1–8 is a truncated form of dynorphin A ...

and

dynorphin B Dynorphin B, also known as rimorphin, is a form of dynorphin and an endogenous opioid peptide with the amino acid sequence Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Gln-Phe-Lys-Val-Val-Thr. Dynorphin B is generated as a proteolytic cleavage product of leumorp ...

. It is derived from the precursor protein prodynorphin, encoded by the ''PDYN'' gene. Big dynorphin is notable for its potent activity at opioid receptors and its role in modulating pain, stress, emotion, and neurophysiological functions such as learning and memory. Big dynorphin has the

amino acid sequence Protein primary structure is the linear sequence of amino acids in a peptide or protein. By convention, the primary structure of a protein is reported starting from the amino-terminal (N) end to the carboxyl-terminal (C) end. Protein biosynthe ...

: Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-Leu-Lys-Trp-Asp-Asn-Gln-Lys-Arg-Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Gln-Phe-Lys-Val-Val-Thr. It has

nociceptive In physiology, nociception , also nocioception; ) is the sensory nervous system's process of encoding noxious stimuli. It deals with a series of events and processes required for an organism to receive a painful stimulus, convert it to a molecular ...

and anxiolytic-like properties, as well as effects on memory in mice. Big dynorphin is a principal

endogenous Endogeny, in biology, refers to the property of originating or developing from within an organism, tissue, or cell. For example, ''endogenous substances'', and ''endogenous processes'' are those that originate within a living system (e.g. an ...

, agonist at the human kappa-opioid receptor.

Receptor binding and activity

Big dynorphin primarily acts as an agonist at κ-opioid receptors, where it exhibits high potency and efficacy, leading to analgesic, dysphoric, and sedative effects. Additionally, evidence suggests it may also interact with NMDA (N-methyl-D-aspartate) receptors independently of opioid pathways, contributing to effects on synaptic plasticity and neurotoxicity.

Physiological and behavioral effects

Research has implicated big dynorphin in a variety of physiological processes: * Pain modulation: Like other dynorphins, big dynorphin can produce analgesic effects but may also induce hyperalgesia in certain contexts. * Emotion and stress: Big dynorphin is involved in the regulation of anxiety-like and depressive-like behaviors, often through its activation of the dynorphin/KOR system. * Memory and learning: It has been shown to impair spatial memory in rodent models, possibly through NMDA receptor modulation.

Pathophysiological roles

Big dynorphin levels are altered in several neuropsychiatric and neurodegenerative conditions: * Depression and addiction: Alterations in dynorphin signaling, including big dynorphin, are linked to substance use disorders and stress-related mood disorders.

References

Neuropeptides Kappa-opioid receptor agonists Opioid peptides {{biochem-stub

Receptor binding and activity

Physiological and behavioral effects

Pathophysiological roles

See also

References