Search results for "Enkephalin"
showing 10 items of 24 documents
Activation of MORs in the VTA induces changes on cFos expression in different projecting regions: Effect of inflammatory pain.
2019
Abstract Chronic pain is a worldwide major health problem and many pain-suffering patients are under opioid based therapy. Epidemiological data show that pain intensity correlates with the risk of misuse of prescription opioids, and other drugs of abuse including alcohol. This increased vulnerability to suffer Substance Use Disorders could be, in part, caused by functional changes that occur over the mesocorticolimbic system, a brain pathway involved in reward processing and addiction. Previous data in rats revealed that inflammatory pain desensitizes mu opioid receptors (MORs) in the ventral tegmental area (VTA). As a consequence, pain alters dopamine release in the nucleus accumbens (NAc)…
δ 1‐OPIOID receptor‐mediated controlofacetylcholine (ACh) release in human neocortex slices
1998
In slices of human neocortex, prelabelled with [3H]-choline, the release of [3H]-acetylcholine reflects the evoked release of endogenous acetylcholine which was elicited by the same electrical stimulation paradigm. [3H]-Acetylcholine release was depressed by the delta-opioid receptor agonist D-Pen2-D-Pen5-enkephalin. When the nerve endings were depolarized by elevating extracellular potassium the evoked [3H]-acetylcholine release was similarly depressed by D-Pen2-D-Pen5-enkephalin in the absence, but not in the presence, of tetrodotoxin which blocks action potential propagation. Therefore, the delta-opioid receptor inhibiting [3H]-acetylcholine release should not be located to cholinergic n…
Regional distribution of opioidergic nerves in human and canine prostates
1989
The regional distribution of opioidergic nerves in the juvenile and adult human prostate and in the adult canine prostate has been studied immunohistochemically using well-characterized polyclonal antisera against multiple opioid peptides. Nerves displaying immunoreactivity (ir) for the proenkephalin (PRO-ENK) derivatives met-enkephalin (ME), leuenkephalin (LE), octapeptide, and heptapeptide (ordered in decreasing frequency) were present in the dorsolateral stroma of human prostate. In canine prostate, the situation was similar, but the number of opioid-ir nerve fibers was lower than in human prostate. In both species, staining for the prodynorphin (PRO-DYN) derivatives dynorphin A and alph…
Lack of genetic association of neutral endopeptidase (NEP) with complex regional pain syndrome (CRPS)
2010
Complex regional pain syndrome (CRPS) is a condition that is characterized by severe pain and exaggerated neurogenic inflammation, which may develop after injury or surgery. Neurogenic inflammation is mediated by neuropeptides, such as calcitonin gene-related peptide (CGRP) and substance P (SP) that are released from nociceptors. Genetic factors may play a role in CRPS as was suggested by the occurrence of familial cases and several genetic association studies investigating mainly the human leukocyte antigen (HLA) system. Here we investigated the role of neutral endopeptidase (NEP), a key enzyme in neuropeptide catabolism. NEP dysfunction resulting in reduced inactivation of neuropeptides m…
On the opioid receptor subtype inhibiting the evoked release of 3H-noradrenaline from guinea-pig atria in vitro
1986
1. Guinea-pig isolated atria were incubated and loaded with 3H-(−)-noradrenaline. The intrinsic nerves were stimulated with trains of 5 or 35 field pulses (4 Hz), and the evoked efflux of 3H-noradrenaline and of total tritium was determined in the presence of atropine, corticosterone, desipramine, and phentolamine by liquid scintillation spectrometry. 2. Ethylketocyclazocine (1.4 nmol/l, IC50), MR 2033 (9.1 nmol/l), dynorphin A (1–13) (25 nmol/l, peptidase inhibitors present), etorphine (71 nmol/l), and [d-Ala2, d-Leu5]-enkephalin (>10 μmol/l, peptidase inhibitors present) inhibited the stimulation-evoked efflux of 3H-noradrenaline in a concentration-dependent manner, but not morphine up to…
Ikaros-1 couples cell cycle arrest of late striatal precursors with neurogenesis of enkephalinergic neurons
2010
et al.
Binding of [3H][D-Ala2, MePhe4, Gly-ol5] Enkephalin, [3H][D-Pen2, D-Pen5]Enkephalin, and [3H]U-69,593 to Airway and Pulmonary Tissues of Normal and S…
1997
Abstract Bhargava, H. N., V. M. Villar, J. Cortijo and E. J. Morcillo. Binding of [3H][D-Ala2, MePhe4, Gly-ol5]enkephalin, [3H][D-Pen2, D-Pen5]enkephalin, and [3H]U-69,593 to airway and pulmonary tissues of normal and sensitized rats. Peptides 18(10) 1603–1608, 1997.—The role of endogenous opioid peptides in the regulation of bronchomotor tone, as well as in the pathophysiology of asthma is uncertain. We have studied the binding of highly selective [3H]labeled ligands of μ-([D-Ala2, MePhe4, Gly-ol5]enkephalin; DAMGO), δ ([D-Pen2, D-Pen5]enkephalin; DPDPE), and κ-(U-69,593) opioid receptors to membranes of trachea, main bronchus, lung parenchyma and pulmonary artery obtained from normal (uns…
Degrees of freedom effect on fragmentation in tandem mass spectrometry of singly charged supramolecular aggregates of sodium sulfonates
2012
The characteristic collision energy (CCE) to obtain 50% fragmentation of positively and negatively single charged noncovalent clusters has been measured. CCE was found to increase linearly with the degrees of freedom (DoF) of the precursor ion, analogously to that observed for synthetic polymers. This suggests that fragmentation behavior (e.g. energy randomization) in covalent molecules and clusters are similar. Analysis of the slope of CCE with molecular size (DoF) indicates that activation energy of fragmentation of these clusters (loss of a monomer unit) is similar to that of the lowest energy fragmentation of protonated leucine-enkephalin. Positively and negatively charged aggregates be…
Regional differences in mu-opioid receptor-dependent modulation of basal dopamine transmission in rat striatum
2016
Abstract The nigrostriatal dopamine system is implicated in the regulation of reward and motor activity. Dopamine (DA) release in dorsal striatum (DS) is controlled by the firing rate of DA neurons in substantia nigra pars compacta. However, influences at terminal level, such as those involving activation of mu opioid receptors (MORs), can play a key role in determining DA levels in striatum. Nonetheless, published data also suggest that the effect of opioid drugs on DA levels may differ depending on the DS subregion analyzed. In this study, in vivo microdialysis in rats was used to explore this regional dependence. Changes in basal DA levels induced by local retrodialysis application of DA…
Shell/core differences in mu- and delta-opioid receptor modulation of dopamine efflux in nucleus accumbens
2008
The mu- and delta-opioid receptors located at the terminal level in nucleus accumbens are involved in the opiate modulation of dopamine release in this brain area. However, recent studies suggest that the effects of opioid drugs on the core subregion of nucleus accumbens may completely differ from those observed in the shell. We used in vivo microdialysis to simultaneously apply selective mu- and delta-opioid receptor agonists and to measure extracellular levels of dopamine in three subregions of the accumbens, namely shell, core, and the transition zone between them. The regional analysis of these subregions of the accumbens demonstrated that basal levels of dopamine and its metabolites we…