Disease relevance of Methionine enkephalin

• This probe hybridizes specifically to a species of poly(A)-RNA from adrenal medulla and human pheochromocytoma, (1400--1450 bases), and also to [Met]enkephalin-containing pro-opiomelanocortin mRNAs from bovine pituitary (1200 bases) and from mouse pituitary tumor cell (1100 bases) [1].
• In sequence analysis, the thoracic ganglion yielded 3 pmol of [Leu]enkephalin and approximately 1 pmol of [Met]enkephalin [2].
• In locus coeruleus neurons, substance P (SP) suppresses an inwardly rectifying K+ current via a pertussis toxin-insensitive guanine nucleotide binding protein (G protein; GnonPTX), whereas somatostatin (SOM) or [Met]enkephalin (MENK) enhances it via a pertussis toxin-sensitive G protein (GPTX) [3].
• In this study, we show that noscapine inhibits the proliferation of rat C6 glioma cells in vitro (IC(50) = 100 microm) and effectively crosses the blood-brain barrier at rates similar to the ones found for agents such as morphine and [Met]enkephalin that have potent central nervous system activity (P < or = 0.05) [4].
• Circulating [Met]enkephalin and catecholamine responses to acute hypotension and hypertension in anaesthetized greyhounds [5].

Psychiatry related information on Methionine enkephalin

• Social interaction increases the extracellular levels of [Met]enkephalin in the nucleus accumbens of control but not of chronic mild stressed rats [6].
• Met-Enk injected i.p. produced an increase of horizontal and vertical locomotor activity in the open field that was reversed by i. p. administration of anti-Met-Enk-Ig and qNtx [7].

High impact information on Methionine enkephalin

• Production of [Met]enkephalin by cathepsin L occurred by proteolytic processing at dibasic and monobasic prohormone-processing sites [8].
• Cellular studies showed the colocalization of cathepsin L with [Met]enkephalin in secretory vesicles of neuroendocrine chromaffin cells by immunofluorescent confocal and immunoelectron microscopy [8].
• In vivo administration of antibodies against opioid peptides indicates that the effects of IL-1 and CRF are mediated by beta-endorphin and, in addition, by dynorphin A and [Met]enkephalin, respectively [9].
• The high potency of this compound parallels that of [Met]enkephalin, which was previously demonstrated in vertebrate plasma and invertebrate hemolymph [10].
• [Leu]- and [Met]enkephalin from thoracic ganglia of the shore crab Carcinus maenas have been purified to homogeneity by a reversed-phase HPLC procedure [2].

Chemical compound and disease context of Methionine enkephalin

• Both GABA and [Met]enkephalin immunoreactivities were found in varicose nerve fibers, forming diffuse networks which were denser in the rostral than in the caudal part of each ganglion [11].
• Plasma methionine-enkephalin (Met-Enk) immunoreactivity has been determined in 24 patients with varying degrees of renal impairment and 14 patients with hepatic failure [12].
• The purpose of the present study is to determine whether NEP hydrolyzes Met-Enk and SP in the carotid body and if so whether these peptides contribute to phosphoramidon-induced potentiation of the sensory response to hypoxia [13].
• The lower reduction in norepinephrine release and vascular responsiveness by Met-Enk and Leu-Enk in SHR suggests an insufficient regulation of the vascular adrenergic neurotransmission by the opioid peptides in this model of hypertension [14].
• Effects of hemorrhage on vasopressin and Met-Enk releases in blood and cerebrospinal fluid in dogs [15].

Biological context of Methionine enkephalin

• [Met]Enkephalin-containing proteins of 8600 and 12,600 daltons have been isolated from acid extracts of bovine adrenal medulla and purified to homogeneity, and their sequences have been determined by a combination of automated Edman degradation, tryptic mapping, and enzymatic time-course hydrolysis [16].
• Ethanol acceptance as a function of genotype amounts of brain [Met]enkephalin [17].
• The presence of [Met]enkephalin, a pentapeptide derived from proenkephalin, in these two brain areas is consistent with a synthetic role for this mRNA and implicates proenkephalin gene expression in the control of motor function [18].
• FPI attenuates vasodilation and cGMP production by methionine enkephalin (Met) and leucine enkephalin (Leu) and reverse dynorphin (Dyn) from a dilator to a constrictor [19].
• Between 125 and 140 days of gestation, plasma free Met-Enk concentrations were similar and significantly higher in the intact and HX + T4 groups than those measured in the HX + saline fetal sheep [20].

Anatomical context of Methionine enkephalin

• It has been shown that [35S]methionine is incorporated into the [Met]enkephalin sequences of a 22,000-dalton enkephalin-containing protein in the adrenal medulla [21].
• Studies with [35S]methionine indicate that the 22,000-dalton [Met]enkephalin-containing protein in chromaffin cells is a precursor of [Met]enkephalin [21].
• Two [Met]enkephalin-containing polypeptides have been purified from extracts of bovine and adrenal chromaffin granules [22].
• These findings indicate a previously uncharacterized biological role for secretory vesicle cathepsin L in the production of [Met]enkephalin, an endogenous peptide neurotransmitter [8].
• Although the abundance of preproenkephalin-like mRNA in rat testis was comparable to that in rat brain, the testicular content of proenkephalin-derived [Met]enkephalin sequences was less than 4% of the rat brain content [23].

Associations of Methionine enkephalin with other chemical compounds

• Incubation of chromaffin cells with [3H]tyrosine and [35S]methionine for 3 days results in incorporation of 3H and 35S into [Met]enkephalin and 3H incorporation into [Leu]enkephalin, demonstrating de novo enkephalin synthesis [24].
• The precise localization of proenkephalin and [Met]enkephalin immunoreactivities was compared to the distribution of oxytocin and vasopressin in serial 5-micron sections through the magnocellular nuclei [25].
• Stimulated cosecretion of endopin 1 with chromaffin granule components, [Met]enkephalin and a cysteine protease known as "prohormone thiol protease," demonstrated localization of endopin 1 to functional secretory vesicles [26].
• We, therefore, determined the effects of both beta-EP and Met-Enk, alone or in combination with naloxone, on FSH-induced progesterone (P) secretion by cultured granulosa cells [27].
• Daily administration of nicotine for 14 days increased Met-Enk content and PPE mRNA in the striatum of mice as well [28].

Gene context of Methionine enkephalin

• The greatest numbers of nerve cell bodies contained AChE, followed in decreasing order by SP, mENK and NPY [29].
• CGRP was the most potent stimulatory neurotransmitter in RA fibroblasts whereas the sympathetic adenosine, NE, beta-endorphin, and MENK were inhibitory [30].
• The connectivity experiments employed five combinations of fluorescent tracer injection and were combined with immunohistochemical localization of either neuropeptide Y (NPY), met-enkephalin (mENK) or the vasoactive intestinal polypeptide (VIP)/peptide histidine isoleucine (PHI) group [31].
• In RA fibroblasts, beta-endorphin and MENK inhibited IL-8 secretion at 10(-9) to 10(-7) M (p < 0.01), whereas in OA fibroblasts the dose response curve was shifted to lower concentrations (10(-12) M, 10(-11) M; p < 0.01) [30].
• Subsequently, CGRP, Met-Enk or TH antisera were applied to these sections and the resulting brown diaminobenzidine reaction product in the cytoplasm was examined [32].

Analytical, diagnostic and therapeutic context of Methionine enkephalin

• A highly specific radioimmunoassay for one of the putative adrenomedullary [Met]enkephalin precursors, BAM-12P (Tyr-Gly-Gly-Phe-Met-Arg-Arg-Val-Gly-Arg-Pro-Glu-OH), has been developed [33].
• Sequence analysis of the 3600-dalton polypeptide has not been completed, but the polypeptide has been shown to contain a single [Met]enkephalin sequence followed by an -Arg-Phe linkage that forms the carboxyl terminus of the molecule [34].
• Within 3 days in coculture with endothelial cells, but not with unrelated control cells, PC12 cells synthesized increased levels of [Met]enkephalin [35].
• We have demonstrated the existence of Met-Enk-Arg6-Gly7-Leu8 together with Met-Enk, Leu-Enk and Met-Enk-Arg6-Phe7 in human gastric antrum, using high performance liquid chromatography (HPLC) coupled with radioimmunoassays for these opioid peptides [36].
• One day after surgery, the adrenal dialysis system was connected to a perfusion pump and Ringer solution or a Ringer solution containing Met-Enk, naloxone (Nal), or a combination of Met-Enk and Nal was used for dialysis; dialysate fractions were collected at 5-min intervals [37].

References