Disease relevance of leucine enkephalin

• Methionine-enkephalin and leucine-enkephalin in human sympathoadrenal system and pheochromocytoma [1].
• Pertussis toxin (PTX) pretreatment abolished LE effects on beta1-AR stimulation [2].
• Leucine-enkephalin produced electrical seizure activity in rats as young as 2 days. beta-Endorphin administration was associated with seizures at the fifth postnatal day, with a high incidence of apnea resulting in death in animals as young as 6 hours [3].
• Serum leucine-enkephalin in bronchial carcinoma and its relation to tumour location [4].
• Another population of about 9% of the retrogradely labeled displaced ganglion cells was shown to contain leucine-enkephalin-like immunoreactivity [5].

Psychiatry related information on leucine enkephalin

• DPen2-[DPen5]enkephalin, a delta opioid receptor-selective analog of [Leu]enkephalin, impairs avoidance learning in an automated shelf-jump task in rats [6].
• For example some agents including [Leu]enkephalin and MK801 cause amnesia 4 or more h after training.(ABSTRACT TRUNCATED AT 250 WORDS)[7]
• The distribution of substance P and leucine-enkephalin in selected regions of brain obtained postmortem from patients with Huntington's disease and from neurologically normal persons has been studied with immunocytochemical techniques [8].
• Also like [leu]enkephalin, tyr-gly-gly did not alter locomotor activity [9].
• After rats received electroacupuncture (EA), leucine-enkephalin (LEK) content in striatum and dopamine (DA) concentration in both brain stem and diencephalon markedly increased, and noradrenaline (NA) level in telencephalon definitely decreased with an obvious elevation of pain threshold [10].

High impact information on leucine enkephalin

• The primary structure of a precursor protein that contains beta-neo-endorphin, dynorphin and a third leucine-enkephalin sequence with a carboxyl extension has been deduced from the nucleotide sequence of cloned DNA complementary to the porcine hypothalamic mRNA encoding it [11].
• Impulse activity differentially regulates [Leu]enkephalin and catecholamine characters in the adrenal medulla [12].
• Surgical denervation of the adrenal gland or pharmacologic blockade of synaptic transmission, treatments known to decrease catecholamine traits, increased [Leu]enkephalin content [12].
• Regulation of the putative peptide neurohumour [Leu]enkephalin and the catecholaminergic enzymes tyrosine hydroxylase and phenylethanolamine-N-methyl-transferase was examined in the rat adrenal medulla in vivo and in vitro [12].
• Medullas explanted to culture exhibited a 50-fold rise in [Leu]enkephalin in 4 days, whereas tyrosine hydroxylase remained constant, and phenylethanolamine-N-methyltransferase decreased to a new baseline level [12].

Chemical compound and disease context of leucine enkephalin

• In untreated animals dense networks of methionine- and leucine-enkephalin-like immunoreactive fibres were found in the coeliac ganglion [13].
• These results may reflect an altered interaction between leucine-enkephalin and noradrenaline in essential hypertensives compared to normotensives, possibly contributing to hypertension [14].

Biological context of leucine enkephalin

• The hydrolysis of [Leu]enkephalin and substance P by purified pig kidney endopeptidase (EC 3.4.24.11) and synaptic membranes prepared from pig caudate nuclei has been compared [15].
• Under the conditions optimal for beta-endorphin binding, leucine-enkephalin has one-fourth to one-third as many binding sites as beta-endorphin and its affinity is 7--10% that of beta-endorphin [16].
• The IC50 concentration (8 nM) was similar to that reported for [Leu]enkephalin hydrolysis by the purified endopeptidase [Fulcher, I. S., Matsas, R., Turner, A. J. & Kenny, A. J. (1982) Biochem. J. 203, 519-522] [15].
• Both control and kindled rats showed nonspecific inhibition of calcium/calmodulin-stimulated phosphorylation in the post hoc assay by corticotropin and by [Leu]enkephalin [17].
• The sequence of an extended cDNA, 62 bases in length, was found to correspond exactly to that expected from the amino acid sequence of peptide E (a bovine adrenal peptide containing [Met]- and [Leu]enkephalin sequences) [18].

Anatomical context of leucine enkephalin

• After 1 year the experimental hamsters showed a significantly lower concentration of leucine-enkephalin-like immunoreactive substance in the basal ganglia than the control hamsters [19].
• Both methionine- and leucine-enkephalin were detected in tumor tissue by immunocytochemistry, with immunoreactivity related to the cortical cytoplasm of tumor cells, but not to cell nuclei [20].
• These findings indicate that (a) leucine-enkephalin has two receptor sites on the sphincter of Oddi--one at the serotonergic neurons and the other at noncholinergic, nonadrenergic inhibitory neurons, and (b) opioid peptides participate in the intramural excitatory pathway to the sphincter of Oddi [21].
• Alkali secretion by fundic mucosa of Rana temporaria, or antral mucosa of Rana catesbeiana, was unaffected by morphine, methionine-enkephalin and leucine-enkephalin, two enkephalin analogues, or the opiate antagonist naloxone [22].
• In the guinea pig ileum longitudinal muscle preparation it is about 700 times more potent than [Leu]enkephalin [23].

Associations of leucine enkephalin with other chemical compounds

• Digestion with trypsin and carboxypeptidase B yields [Met]enkephalin and [Leu]enkephalin in a ratio of almost 7 to 1 [24].
• Substance P and [Leu]enkephalin are hydrolyzed by an enzyme in pig caudate synaptic membranes that is identical with the endopeptidase of kidney microvilli [15].
• Prodynorphin-derived peptides [dynorphin A (Dyn A)-(1-17), Dyn A-(1-8), Dyn B, alpha-neo-endorphin, and beta-neo-endorphin] and proenkephalin-derived peptides [[Leu]enkephalin [( Leu]Enk) and [Met]enkephalin-Arg6-Gly7-Leu8 [( Met]Enk-Arg-Gly-Leu]) in selected brain areas of the rat were measured by specific radioimmunoassays [25].
• The morphogenic opiate pentapeptide leucine-enkephalin (lenk) in a hydrated dimyristoylphosphatidylcholine (DMPC) bilayer is studied using NMR spectroscopy and molecular dynamics simulation [26].
• Similar partial restoration of vascular and biochemical parameters was observed for Leu and Dyn. CONCLUSIONS: These data show that ET-1, in concentrations similar to that present in cerebrospinal fluid after FPI, increases O2- production [27].

Gene context of leucine enkephalin

• Submucous neurons had all the above except neuropeptide Y, methionine-enkephalin, leucine-enkephalin, and bombesin [28].
• Cells immunoreactive for LENK and NT were concentrated in the anterior NTS; 5.5-7.5% of the LENK cells were double-labeled bilaterally, while 11% (ipsilateral) and 21% (contralateral) of the NT immunoreactive cells were double-labeled [29].
• A few varicose fibers were labeled with antisera against neurotensin (NT), leucine-enkephalin (L-ENK), and the vasoactive intestinal polypeptide (VIP) [30].
• Immunohistochemical localization of tyrosine hydroxylase, substance P, neuropeptide-Y and leucine-enkephalin in developing human retinal amacrine cells [31].
• Colchicine treatment alone resulted in appearance of galanin-, dynorphin-, cholecystokinin-, [Leu]enkephalin- and thyrotropin-releasing hormone-positive cells [32].

Analytical, diagnostic and therapeutic context of leucine enkephalin

• At least 25% of the opioid activity as measured by radioreceptor assay is present as [Met]- and [Leu]enkephalin [33].
• Isolated crustacean [Leu]enkephalin shows physiological properties identical to synthetic [Leu]enkephalin in our bioassay [34].
• The peptides included leucine-enkephalin, beta-neoendorphin, dynorphin-A8, and dynorphin-B, as identified by gel filtration and reverse phase HPLC followed by RIA using peptide-specific antisera [35].
• High pressure liquid chromatography (HPLC) elution of enkephalin immunoreactivity matched that of synthetic methionine-enkephalin, leucine-enkephalin, and methionine-sulfoxide-enkephalin standards [36].
• [Leu]enkephalin-induced enhancement of avoidance acquisition was also observed in Sprague-Dawley rats; the intraperitoneal injection of 10 micrograms/kg LE, administered 5 minutes before training, enhanced acquisition of a jump-up one-way active avoidance response [37].

References