κ-opioid receptor (KOR) [4][5][6]; NMDA receptor (direct or indirect) [2][3][4]; AMPA/kainate receptor [3]

Inducing neuronal death, dynorphin A (10 μM, 4 h/72 h) raises the amount of cytochrome c produced from mitochondria and caspase-3 activity in mouse striatal neurons [3]. At 33 μM, during four hours, dynorphin A raises [Ca2+]i and significantly reduces neuronal viability [4]. In isolated neural lobes, the release of vasopressin (VP) is inhibited by 1 μM of dynorphin A [5].

---

Prodynorphin (209-225),porcine |Dynorphin A| (CAS#: 80448-90-4) (1-17 fragment) at 10 nM to 10 μM caused concentration-dependent increases in caspase-3 activity in mouse striatal neurons after 4 h and 72 h exposure, with maximal activation at 10 μM. The caspase-3 activity was completely blocked by the caspase-3 inhibitor Ac-DEVD-CHO (1 μM). [3]
Dynorphin A (1-17) (10 μM) induced mitochondrial release of cytochrome c into the cytosol at 4 h and 72 h, which was significantly attenuated by the AMPA/kainate antagonist CNQX (10 μM) but not by naloxone (10 μM) or MK801 (10 μM). [3]
Dynorphin A (1-13) (33 μM) caused acute increases in intracellular calcium concentration ([Ca2+]i) in mouse spinal cord neurons, similar to NMDA. The elevation was blocked by MK-801 (10 μM) and partially attenuated by (-)-naloxone (100 μM). [4]
Dynorphin A (1-13) at concentrations of 10 μM and 33 μM induced significant neuronal loss in spinal cord cultures after 24-48 h, which was prevented by co-administration of MK-801 (10 μM) or by AP-5 (100 μM) or 7-chlorokynurenic acid (100 μM). [4]
In contrast, the κ-opioid receptor antagonists (-)-naloxone (3 μM) and nor-binaltorphimine (3 μM) exacerbated dynorphin A (1-13)-induced neuronal loss, while the inactive stereoisomer (+)-naloxone had no effect. [4]
In isolated rat neural lobe, dynorphin A (1-8) (1 μM) significantly inhibited electrically evoked vasopressin release (S2/S1 ratio: 0.547 ± 0.037 vs control 0.759 ± 0.017). Dynorphin A (1-13) and (1-17) at 1 μM did not affect evoked vasopressin release. Naloxone (10 μM) also had no effect. [5]

Male rats that are dehydrated for 24 hours are not able to release vasopressin (VP) when given a single dose of 1 μg/2 μL of intracerebroventricular injection of dysorphin A [5]. In ddY mice, intracerebroventricular injections of 500 pmol/5 μL each day for four days can ameliorate behavioral problems caused by stress and control the brain's 5-HTergic system [6].

---

Dynorphin A (1-17) (0.46 nmol, i.c.v.) and dynorphin A (1-13) (0.65 nmol, i.c.v.) significantly inhibited vasopressin release in 24 h water-deprived male rats 30 min after injection, with dynorphin A (1-17) being more potent. Dynorphin A (1-8) (1.02 nmol or 5.09 nmol, i.c.v.) had no effect unless co-administered with the endopeptidase-24.15 inhibitor cFPAAF-pAB (10 nmol), which then suppressed vasopressin plasma levels. [5]
Intracerebroventricular injection of dynorphin A (1-17) antiserum increased vasopressin levels at 20 and 60 min, while dynorphin A (1-13) antiserum increased vasopressin at 60 min, indicating tonic inhibition by endogenous dynorphin. [5]
Dynorphin A (1-13) (1500 pmol/5μL, i.c.v.) administered daily for 4 days (10 min before each training) significantly reduced the number of escape failures in a learned helplessness paradigm in mice on day 4 (F(4,35)=3.12, p=0.037; Dunn's test p<0.01). This effect was blocked by the κ-opioid receptor antagonist nor-binaltorphimine (4.9 nmol/kg, s.c.). [6]
Dynorphin A (1-13) did not affect plasma corticosterone levels (stressed+Dyn: 12.6±1.3 ng/mL vs stressed: 11.2±0.7 ng/mL) nor locomotor activity (no significant differences among groups). [6]
Dynorphin A (1-13) reversed the increase in 5-HIAA content and 5-HIAA/5-HT ratio in the amygdala induced by repeated footshock stress, bringing them back to non-stressed control levels. [6]

Caspase-3 activity assay: Mouse striatal neurons were lysed in harvesting buffer (25 mM HEPES pH 7.5, 5 mM EDTA, 1 mM EGTA, 5 mM MgCl2, 10 mM sucrose, 5 mM DTT, 1% CHAPS, 10 μg/ml pepstatin, 10 μg/ml leupeptin, 1 mM PMSF). Lysates (25 μg protein) were incubated at 37°C with 50 μM Ac-DEVD-AMC substrate in assay buffer (25 mM HEPES pH 7.5, 10% sucrose, 0.1% CHAPS, 1 mM DTT). Fluorescence (ex360/em460 nm) was measured. Specificity confirmed by Ac-DEVD-CHO (1 μM). [3]
Measurement of monoamines (5-HT and 5-HIAA): Brain regions (amygdala, hippocampus) were homogenized in 0.2 M perchloric acid containing isoproterenol as internal standard, placed on ice for 30 min, centrifuged at 20,000×g for 15 min at 4°C. Supernatants were adjusted to pH 3 with 1 M sodium acetate and injected into HPLC with an ODS column and electrochemical detector (potential +750 mV). Mobile phase: 0.1 M citric acid, 0.1 M sodium acetate pH 3.6, 17% methanol, 180 mg/L sodium 1-octanesulfonate, 5 mg/L EDTA. Flow rate 500 μL/min. [6]

Cell Viability Assay [3]
Cell Types: Mouse Striatal Neurons
Tested Concentrations: 10 μM
Incubation Duration: 0, 24, 48, 72 hrs (hours)
Experimental Results: Induction of neuronal death (identified by fragmentation and destruction of cell bodies and neurites ).

---

Primary mouse striatal neuron culture: Embryonic day 15 (E15) ICR mouse striata were dissected, dissociated, and grown in serum-free DMEM/F-12 supplemented with 2% B27, 1 μg/ml linoleic acid, 25 μg/ml insulin, 1% antibiotic/antimycotic. Cells were seeded on poly-D-lysine coated plates (4×10^5 cells/well) at 35°C, 5% CO2. For viability, time-lapse digital microscopy was used; neurons were treated with dynorphin A (1-17) (10 μM) with or without Z-DEVD-FMK (30 μM) for 48-72 h. Dead neurons identified by fragmentation and destruction of cell body and neurites. [3]
Mitochondrial cytochrome c release assay: Striatal neurons were harvested in ice-cold buffer A (20 mM HEPES-KOH pH 7.5, 10 mM KCl, 1.5 mM MgCl2, 1 mM EDTA, 1 mM EGTA, 1 mM DTT, 0.1 mM PMSF, 250 mM sucrose). Homogenates were centrifuged at 750×g for 10 min, then supernatant at 12,000×g for 30 min to obtain cytosolic fraction and mitochondrial pellet. Equal proteins (50 μg) were immunoprecipitated with anti-cytochrome c antibody, separated by SDS-PAGE, transferred to PVDF, and detected by chemiluminescence. [3]
Spinal cord neuron culture: Embryonic day 14 (E14) ICR mouse spinal cords were dissected, minced, trypsinized (0.25% trypsin, 0.01% DNase, 15 min, 35°C), triturated, and plated on poly-D-lysine coated glass-bottom dishes at 20×10^5 cells/cm². Culture medium: Neurobasal with B27 (2%), L-glutamine (0.5 mM), gentamicin (10 μg/ml), and L-glutamate (25 μM on days 0-2, 12.5 μM on days 3-4). [4]
Intracellular calcium measurement: Spinal cord neurons loaded with 10 μM fura-2/AM for 45 min at 35-37°C in growth medium with 25 mM Hepes and 3% DMSO. Ratiometric fluorescence imaging at 340/380 nm excitation, 590 nm emission. [4]
Neural lobe static incubation: Rat neurointermediate lobe was dissected, neural lobe impaled on electrodes, incubated in carbogenated buffer (118 mM NaCl, 4.85 mM KCl, 1.15 mM K2HPO4, 1.15 mM MgSO4, 25 mM NaHCO3, 1.25 mM CaCl2, 0.018% ascorbic acid, 5% BSA) at 37°C. Double stimulus paradigm: first stimulation (S1) in control medium, second (S2) with test compound added 20 min before S2. Stimulation: 1 min at 10 Hz, 2 mA, 2 ms biphasic pulses. Evoked vasopressin release measured by RIA; S2/S1 ratios calculated. [5]

Animal/Disease Models: 24-hour water-deprived male rats [5]
Doses: 1 μg/2 μL
Route of Administration: Intracerebroventricular injection
Experimental Results: Inhibition of vasopressin (VP) release 30 minutes after injection.

---

Animal/Disease Models: Male ddY mice [6]
Doses: 15, 150, 1500 pmol/5 μL per day for 4 days.
Route of Administration: lateral ventricular injection.
Experimental Results: Reduce the failure of escape from electric shock caused by repeated stress.

---

In vivo rat experiment (vasopressin release): Male Wistar rats (200-220 g) were water-deprived for 24 h. A polyethylene cannula was placed in the right lateral ventricle under Hypnorm anesthesia. After one week recovery, rats received i.c.v. injection (2 μl) of dynorphin A fragments dissolved in saline. Control received saline or normal rabbit serum. Thirty min later, rats were decapitated, trunk blood collected in EDTA tubes, centrifuged (2000×g, 20 min, 4°C). Plasma vasopressin measured by RIA after solid-phase extraction on C8 columns. [5]
In vivo mouse experiment (learned helplessness): Male ddY mice (9 weeks) were implanted with a lateral ventricle guide cannula (AP +0.6 mm, ML +1.7 mm, DV -4.5 mm from bregma) under pentobarbital anesthesia (50 mg/kg i.p.). After recovery, mice were exposed to inescapable electric footshock (0.6 mA, 30 s duration, 30 s interval) for 30 min on day 0. From day 1 to day 4, dynorphin A (1-13) (1500 pmol/5μL, i.c.v.) was administered 10 min before each active conditioned avoidance training (30 trials/day; avoidance: 3 s light+buzzer, escape: 30 s footshock 0.6 mA; inter-trial interval 30 s). Nor-binaltorphimine (4.9 nmol/kg s.c.) was given 25 min before training. Number of escape failures recorded. On day 4 after behavioral test, mice were sacrificed by microwave irradiation (5 kW, 1.4 s), brains dissected for monoamine analysis. Trunk blood collected for corticosterone ELISA. [6]

Dynorphin A (1-17) at 10 μM induced significant apoptosis in striatal neurons via caspase-3 activation and cytochrome c release. [3]
Dynorphin A (1-13) at 33-100 μM caused concentration-dependent neurotoxicity in spinal cord neurons, with enhanced toxicity by κ-opioid receptor antagonists, indicating that κ-receptor activation may be neuroprotective. [4]
No acute systemic toxicity reported.

[1]. Dynorphin A as a Potential Endogenous Ligand for Four Members of the Opioid Receptor Gene Family. J Pharmacol Exp Ther. 1998 Jul;286(1):136-41.

[2]. Monoclonal antibodies as novel neurotherapeutic agents in CNS injury and repair. Int Rev Neurobiol. 2012;102:23-45.

[3]. Dynorphin A (1–17) induces apoptosis in striatal neurons in vitro through AMPA/kainate receptor-mediated cytochrome c release and caspase-3 activation. Neuroscience. 2003;122(4):1013-23.

[4]. Dynorphin A (1-13) neurotoxicity in vitro: opioid and non-opioid mechanisms in mouse spinal cord neurons. Exp Neurol. 1999 Dec;160(2):361-75.

[5]. Dynorphin-A and vasopressin release in the rat: a structure-activity study. Neuropeptides. 1994 Jun;26(6):371-8.

[6]. Dynorphin a (1-13) alleviated stress-induced behavioral impairments in mice. Biol Pharm Bull. 2014;37(8):1269-73.

A class of opioid peptides, including dynorphin A, dynorphin B, and their smaller fragments. Dynorphins preferentially bind to κ-opioid receptors and have been shown to function as neurotransmitters in the central nervous system.

---

Prodynorphin-derived peptides undergo region-specific post-translational processing: dynorphin A (1-17) is a precursor for dynorphin A (1-8) in most brain areas. Dynorphin A (1-17) is a κ-opioid ligand, while dynorphin A (1-8) is a mixed κ/δ/μ ligand. Endopeptidase-24.15 (EC 3.4.24.15) degrades dynorphin A (1-8) more rapidly than longer fragments. [5]
Dynorphin A (1-13) is a potent fragment that crosses the blood-brain barrier poorly; intracerebroventricular administration is required for central effects. [6]
κ-Opioid receptor stimulation by dynorphin may modulate serotonergic system in the amygdala, as dynorphin A (1-13) reversed stress-induced increase in 5-HIAA/5-HT ratio. [6]

C99H155N31O23

2147.48392033577

2146.191

80448-90-4

Dynorphin A TFA

16133805

White to off-white solid powder

1.5±0.1 g/cm3

1.669

-1.52

33

29

74

153

4600

16

CC[C@H](C)[C@@H](C(=O)N[C@@H](CCCNC(=N)N)C(=O)N1CCC[C@H]1C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC2=CNC3=CC=CC=C32)C(=O)N[C@@H](CC(=O)O)C(=O)N[C@@H](CC(=O)N)C(=O)N[C@@H](CCC(=O)N)C(=O)O)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CC4=CC=CC=C4)NC(=O)CNC(=O)CNC(=O)[C@H](CC5=CC=C(C=C5)O)N

JMNJYGMAUMANNW-FIXZTSJVSA-N

InChI=1S/C99H155N31O23/c1-7-55(6)81(129-86(142)66(28-18-40-112-98(107)108)118-83(139)65(27-17-39-111-97(105)106)120-88(144)70(44-54(4)5)125-89(145)71(46-56-21-9-8-10-22-56)117-79(135)52-115-78(134)51-116-82(138)61(102)45-57-31-33-59(131)34-32-57)94(150)122-67(29-19-41-113-99(109)110)95(151)130-42-20-30-75(130)93(149)121-64(26-14-16-38-101)85(141)124-69(43-53(2)3)87(143)119-63(25-13-15-37-100)84(140)126-72(47-58-50-114-62-24-12-11-23-60(58)62)90(146)128-74(49-80(136)137)92(148)127-73(48-77(104)133)91(147)123-68(96(152)153)35-36-76(103)132/h8-12,21-24,31-34,50,53-55,61,63-75,81,114,131H,7,13-20,25-30,35-49,51-52,100-102H2,1-6H3,(H2,103,132)(H2,104,133)(H,115,134)(H,116,138)(H,117,135)(H,118,139)(H,119,143)(H,120,144)(H,121,149)(H,122,150)(H,123,147)(H,124,141)(H,125,145)(H,126,140)(H,127,148)(H,128,146)(H,129,142)(H,136,137)(H,152,153)(H4,105,106,111)(H4,107,108,112)(H4,109,110,113)/t55-,61-,63-,64-,65-,66-,67-,68-,69-,70-,71-,72-,73-,74-,75-,81-/m0/s1

(2S)-5-amino-2-[[(2S)-4-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-6-amino-2-[[(2S)-2-[[(2S)-6-amino-2-[[(2S)-1-[(2S)-2-[[(2S,3S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[2-[[2-[[(2S)-2-amino-3-(4-hydroxyphenyl)propanoyl]amino]acetyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-4-methylpentanoyl]amino]-5-carbamimidamidopentanoyl]amino]-5-carbamimidamidopentanoyl]amino]-3-methylpentanoyl]amino]-5-carbamimidamidopentanoyl]pyrrolidine-2-carbonyl]amino]hexanoyl]amino]-4-methylpentanoyl]amino]hexanoyl]amino]-3-(1H-indol-3-yl)propanoyl]amino]-3-carboxypropanoyl]amino]-4-oxobutanoyl]amino]-5-oxopentanoic acid

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture and light.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~100 mg/mL (~46.57 mM)
H2O : ≥ 100 mg/mL (~46.57 mM)

Solubility in Formulation 1: ≥ 3 mg/mL (1.40 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 30.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

---

Solubility in Formulation 2: ≥ 3 mg/mL (1.40 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 30.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

---

View More

Solubility in Formulation 3: ≥ 3 mg/mL (1.40 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 30.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

---

 (Please use freshly prepared in vivo formulations for optimal results.)