Browse more peptide research, methods and limitations.
Sulpiride decreased CSF met-enkephalin while paroxetine increased it in chronic tension headache patients after 8 weeks of treatment.
Bach, F W; Langemark, M; Ekman, R; Rehfeld, J F; Schifter, S; Olesen, J · RCT
Delta opioid receptor agonists selectively inhibited nerve-stimulated contractions in human colon tissue without affecting spontaneous contractile activity.
Chamouard, P; Rohr, S; Meyer, C; Baumann, R; Angel, F · In Vitro
Naloxone (5 micromolar) enhanced potassium-evoked oxytocin release from spinal cord synaptosomes, showing tonic opioid inhibition of spinal oxytocin.
Daddona, M M; Haldar, J · In Vitro
Hexarelin effectively stimulated growth hormone secretion in both infant and adult rats through a non-GHRH pathway.
Deghenghi, R; Cananzi, M M; Torsello, A; Battisti, C; Muller, E E; Locatelli, V · Animal Study
Normotensive offspring of hypertensive parents showed altered opioid-ANF interactions during exercise, suggesting early neurohumoral changes before hypertension onset.
Fontana, F; Bernardi, P; Merlo Pich, E; Boschi, S; De Iasio, R; Capelli, M; Carboni, L; Spampinato, S · Cross Sectional
Orally active dual ACE/NEP inhibitors lowered blood pressure in hypertensive rats through combined angiotensin blockade and natriuretic peptide protection.
Fournié-Zaluski, M C; Coric, P; Turcaud, S; Rousselet, N; Gonzalez, W; Barbe, B; Pham, I; Jullian, N; Michel, J B; Roques, B P · Animal Study
Dynorphin-A enhanced macrophage tumoricidal activity under suboptimal activation conditions but not when fully activated.
Hagi, K; Uno, K; Inaba, K; Muramatsu, S · In Vitro
Alpha-neo-endorphin was the dominant prodynorphin peptide in primate brain, with striatal concentrations significantly exceeding cortical levels across all four peptides.
Healy, D J; Meador-Woodruff, J H · Animal Study
Cecropins, magainin, and melittin disrupted mitochondrial coupling, protein import, and respiration, while PR-39 was nearly inert toward mitochondria.
Hugosson, M; Andreu, D; Boman, H G; Glaser, E · In Vitro
L-692,585 produced 4.3 to 7-fold increases in peak GH with maintained efficacy over 15 days of daily dosing and elevated IGF-1 by day 15.
Jacks, T; Hickey, G; Judith, F; Taylor, J; Chen, H; Krupa, D; Feeney, W; Schoen, W; Ok, D; Fisher, M · Animal Study
Peptide opioid agonists (DAMGO, dynorphin analog) were less potent than corresponding non-peptide agonists (morphine, U50,488) in modifying monkey behavior after intramuscular injection.
Jones, D N; Holtzman, S G · Animal Study
Lactoferricin B showed broad-spectrum bactericidal activity at low concentrations, with enhanced effectiveness at lower pH and against actively growing bacteria.
Jones, E M; Smart, A; Bloomberg, G; Burgess, L; Millar, M R · In Vitro
After 12 months of twice-daily subcutaneous GHRH(1-29)NH2 injections (20 μg/kg): - Mean height velocity increased from 4.8 cm/year to 7.2 cm/year (p=0.001) — a 50% improvement - Children who were growing slowest before treatment showed the most dramatic improvement, with some reaching normal growth velocity percentiles - Final height prediction increased by a mean of 3.4 cm (SD 2.6) - IGF-1 levels increased during treatment, as did fasting blood glucose and insulin - Overnight GH levels and GH responses to GHRH testing paradoxically fell during the 12 months of therapy - After stopping treatment, catch-down growth occurred in the first 3 months (HV 3.89 cm/year), though growth velocity returned to pre-treatment baseline by 6–12 months off therapy
Kirk, J M; Trainer, P J; Majrowski, W H; Murphy, J; Savage, M O; Besser, G M ·
Peptidase inhibitor mixture enhanced antinociception from met-enkephalin, beta-endorphin, and electroacupuncture, but not dynorphin-(1-13).
Kishioka, S; Miyamoto, Y; Fukunaga, Y; Nishida, S; Yamamoto, H · Animal Study
The N-terminal to C-terminal beta-endorphin ratio was significantly different in children with autism compared to healthy controls and children with Rett syndrome.
Leboyer, M; Bouvard, M P; Recasens, C; Philippe, A; Guilloud-Bataille, M; Bondoux, D; Tabuteau, F; Dugas, M; Panksepp, J; Launay, J M · Cross Sectional
A highly palatable meal significantly increased post-meal beta-endorphin, pancreatic polypeptide, and neurotensin compared to the same unpalatable meal.
Melchior, J C; Rigaud, D; Chayvialle, J A; Colas-Linhart, N; Laforest, M D; Petiet, A; Comoy, E; Apfelbaum, M · Cross Sectional
Opioid peptides including dynorphins produced voltage-dependent changes in potassium currents in CA3 neurons, resolving contradictory findings from prior studies.
Moore, S D; Madamba, S G; Schweitzer, P; Siggins, G R · In Vitro
Thymosin alpha 1 demonstrated promising antiviral and immune-enhancing effects in early hepatitis B and C trials, suggesting it could complement or replace interferon.
Mutchnick, M G; Ehrinpreis, M N; Kinzie, J L; Peleman, R R · Review
Cloned kappa, delta, and mu opioid receptors showed distinct pharmacological profiles matching decades of predictions from classical pharmacology studies.
Raynor, K; Kong, H; Chen, Y; Yasuda, K; Yu, L; Bell, G I; Reisine, T · In Vitro
IL-1 beta and CRF caused immune cells in inflamed tissue to release opioid peptides that produced local pain relief, blocked by naloxone and anti-opioid antibodies.
Schäfer, M; Carter, L; Stein, C · Animal Study
Each opioid precursor family has a distinct role in the pituitary: beta-endorphin as a hormone, dynorphin as a paracrine modulator of oxytocin, and enkephalins as yet-uncharacterized players.
Schäfer, M K; Martin, R · Review
BPC 157 was the only tested compound that consistently protected against gastric and duodenal ulcers in all three models, regardless of whether given before, during, or after ulcer induction.
Sikiric, P; Seiwerth, S; Grabarevic, Z; Petek, M; Rucman, R; Turkovic, B; Rotkvic, I; Jagic, V; Duvnjak, M; Mise, S · Animal Study
Naloxone restored urinary function in chronic spinal cats but not acute ones, demonstrating opioid system plasticity that contributes to urinary retention after spinal cord injury.
Thor, K B; Roppolo, J R; Kawatani, M; Erdman, S; deGroat, W C · Animal Study
Both met-enkephalin and leu-enkephalin are present in separate neuron populations in the dogfish shark brain, but dynorphin-related peptides were not detected.
Vallarino, M; Bucharles, C; Facchinetti, F; Vaudry, H · Animal Study
Specific beta-endorphin binding sites were localized to pancreatic islet cells, blocked by mu and delta receptor ligands, confirming opioid receptors on insulin-producing cells.
Zhang, M; Zheng, M; Schleicher, R L · In Vitro
ACBC-containing model peptides adopted characteristic stable conformations (helical and extended) that could be leveraged for peptide drug design.
Balaji, V N; Ramnarayan, K; Chan, M F; Rao, S N · In Vitro
The human Y4 receptor was cloned and shown to bind pancreatic polypeptide, NPY, and PYY, expanding the known receptor family for these appetite-regulating peptides.
Bard, J A; Walker, M W; Branchek, T A; Weinshank, R L · In Vitro
GHK-Cu increased wound collagen (hydroxyproline), protein, DNA, and amine oxidase activity in guinea pig skin wounds, with effects requiring the peptide component, not just copper.
Buffoni, F; Pino, R; Dal Pozzo, A · Animal Study
The review synthesizes opioid peptide pharmacology including the novel concept of anti-opioid peptides that counterbalance opioid effects and may drive tolerance.
Cesselin, F · Review
Met-enkephalin, dynorphin, and kappa agonist U50,488 suppressed IL-6-induced HIV-1 expression by over 40% in chronically infected monocyte cells.
Chao, C C; Gekker, G; Sheng, W S; Hu, S; Portoghese, P S; Peterson, P K · In Vitro
Both GHRP-6 and non-peptide GH secretagogues activated Fos expression in the arcuate nucleus and excited arcuate neuroendocrine neurons, confirming central brain actions.
Dickson, S L; Leng, G; Dyball, R E; Smith, R G · Animal Study
Nitrous oxide selectively increased met-enkephalin and met-enkephalin-Arg-Phe in third ventricular CSF without affecting beta-endorphin, leu-enkephalin, or dynorphin.
Finck, A D; Samaniego, E; Ngai, S H · Animal Study
The human Y2 receptor was cloned from hippocampus and shown to selectively bind NPY and PYY but not pancreatic polypeptide.
Gerald, C; Walker, M W; Vaysse, P J; He, C; Branchek, T A; Weinshank, R L · In Vitro
Specific opioid receptors were found in pig granulosa cells and corpora lutea, with receptor numbers increasing during follicular maturation.
Hamada, H; Kishioka, S; Yamoto, M; Nakano, R · In Vitro
Dynorphin A dose-dependently enhanced macrophage phagocytosis through a naloxone-insensitive (non-opioid receptor) mechanism.
Ichinose, M; Asai, M; Sawada, M · In Vitro
One month of GH replacement increased CSF GH and IGF-1 while altering monoamine metabolites, neuropeptides, and opioid peptide concentrations.
Johansson, J O; Larson, G; Andersson, M; Elmgren, A; Hynsjö, L; Lindahl, A; Lundberg, P A; Isaksson, O G; Lindstedt, S; Bengtsson, B A · RCT
Intraluminal peptide factors, released in response to dietary proteins and fats, are key regulators of CCK secretion that coordinate digestion.
Liddle, R A · Review
All tested opioid peptides inhibited arcuate neuron firing, with beta-endorphin affecting 55% of neurons, consistent across different hormonal states.
Lin, J Y; Pan, J T · In Vitro
Anesthesia triggered release of endogenous opioids, ACTH, vasopressin, cortisol, and catecholamines, with constant higher halothane producing more cardiovascular depression.
Luna, S P; Taylor, P M · Animal Study
Brucella species showed broad resistance to 14 antimicrobial peptides, with their outer membranes remaining intact and binding less antimicrobial peptide than susceptible bacteria.
Martínez de Tejada, G; Pizarro-Cerdá, J; Moreno, E; Moriyón, I · In Vitro
Novel backbone-modified GH secretagogues with molecular weight under 500 were the most potent reported, with confirmed anabolic efficacy and a defined bioactive conformation.
McDowell, R S; Elias, K A; Stanley, M S; Burdick, D J; Burnier, J P; Chan, K S; Fairbrother, W J; Hammonds, R G; Ingle, G S; Jacobsen, N E; Mortensen, D L; Rawson, T E; Won, W B; Clark, R G; Somers, T C · Animal Study
Hippocampal dynorphins and enkephalins regulate synaptic transmission efficiency at granule cell synapses, with opioid levels changing dramatically under different physiological and pathological conditions.
Morris, B J; Johnston, H M · Review
Hydrophobic i,i+5 and i,i+8 interactions provide measurable stabilization to alpha-helix structures, with the hydrophobic staple motif contributing to helix nucleation.
Muñoz, V; Serrano, L · In Vitro
The hydrophobic-staple motif (i,i+5 interaction at helix N-terminus) was discovered, validated by NMR, and shown to stabilize alpha-helices and define their N-terminal boundaries.
Muñoz, V; Blanco, F J; Serrano, L · In Vitro
Researchers created a modified version of a myelin peptide (PLP 139-151) by changing a single amino acid — swapping tryptophan for glutamine at position 144. This altered peptide ligand (APL) prevented experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, when the disease was induced with the original peptide. The APL worked by redirecting the immune response. Instead of producing inflammatory Th1 cells that attack myelin, the APL generated T cells that were cross-reactive with the original peptide but produced anti-inflammatory cytokines (IL-4 and IL-10) characteristic of Th2 and Th0 responses. When T cell lines generated with the APL were transferred to other animals, they protected against EAE. This demonstrates that a single amino acid change in an antigenic peptide can fundamentally shift how the immune system responds — from destructive autoimmunity to protective tolerance.
Nicholson, L B; Greer, J M; Sobel, R A; Lees, M B; Kuchroo, V K · Animal Study
Dynorphin B was processed to leu-enkephalin at a 10,000-fold higher rate than dynorphin A in rat striatal extracts.
Nylander, I; Tan-No, K; Winter, A; Silberring, J · In Vitro
Chronic morphine increased dynorphin A and B in the nucleus accumbens and met-enkephalin in the striatum, with distinct withdrawal-phase patterns across brain regions.
Nylander, I; Vlaskovska, M; Terenius, L · Animal Study
Single HPLC method achieved over 80% recovery of multiple opioid and anti-opioid peptides from human plasma in one analytical run.
Partilla, J S; You, J; Rothman, R B · In Vitro
MK-0677 was characterized as the most potent orally active GH secretagogue, with EC50 of 1.3 nM in vitro, oral efficacy in dogs at 0.125 mg/kg, and confirmed anabolic effects in rodents.
Patchett, A A; Nargund, R P; Tata, J R; Chen, M H; Barakat, K J; Johnston, D B; Cheng, K; Chan, W W; Butler, B; Hickey, G · Animal Study
Eschscholtzia californica and Corydalis cava extracts inhibited peroxidase- and tyrosinase-mediated dimerization and oxidation of enkephalin peptides.
Reimeier, C; Schneider, I; Schneider, W; Schäfer, H L; Elstner, E F · In Vitro