Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: CAS:338-69-2 (D-Ala)
 1,901 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An enzyme hydrolyzing succinyl trialanine-4-nitroanilide was extracted from human kidney homogenate and purified by means of gel filtration on Sepharose CL-4B, anion-exchange chromatography on DEAE-Sepharose CL-6B and affinity chromatography on carbobenzoxy-L-Ala-L-Ala-D-Ala-polylysine-agarose. The purified enzyme consists of a single peptide, and its molecular weight was estimated to be about 125 000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified enzyme cleaved the substrate at the bond between succinyl dialanine and alanine-4-nitroanilide and showed a Km value of 2.1 mM at the optimal pH of 8.0. The activity was increased by Ca2+ and Mg2+, but was inhibited by phosphoramidon and ethylenediaminetetraacetic acid. The enzyme cleaved the oxydized insulin B chain, angiotensinogen tetradecapeptide, angiotensin I, angiotensin II, angiotensin III, [Sar1,Ala8]-angiotensin II, bradykinin, des-Pro2-bradykinin, Leu5-enkephalin, Met 5-enkephalin, [D-Ala2,Met5]-enkephalinamide and [D-Ala2-Met5]-enkephalin, but did not cleave [D-Ala2,D-Leu5]-enkephalin. The bonds on the amino side of the hydrophobic amino acids of the peptides were cleaved by the enzyme.
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PMID:Purification and characterization of a human kidney neutral endopeptidase that hydrolyzes succinyl trialanine-4-nitroanilide and biologically active peptides. 388 81

Binding of [3H](d)-N-allylnormetazocine ([3H](d)-NANM) to rat brain membranes is stereospecific, reversible, and saturable (Bmax = 260 fmol/mg of protein) and manifests moderately high affinity (Kd = 20 nM). The rank order of potency among opioidbenzomorphans and phencyclidine (PCP) analogs for competition for [3H](d)-NANM-binding sites is as follows: (d)-NANM = PCP-3-OH greater than (d)-cyclazocine greater than N-ethylphenylcyclohexylamine greater than PCP greater than (l)-cyclazocine = dextrorphan greater than (d/l)-ethylketocyclazocine greater than (d/l)-bremazocine greater than (1)-NANM greater than 1-phenylcyclohexylamine greater than levorphanol. Other opioid ligands, relatively selective for each of the types of opioid binding sites other than sigma, such as morphine (mu), H-Tyr-D-Ala(Me)Phe-NH-CH2-OH (mu), D-Ala2-D-Leu5-enkephalin (delta), tifluadom (kappa), and U 50488 (kappa) as well as etorphine and naloxone were all unable to compete with [3H](d)-NANM for specific binding even at a concentration of 1 microM. Regional distribution studies of [3H](d)-NANM-binding sites show high density in the hippocampus, thalamus, hypothalamus, and amygdala and low density in cerebellum and nonfrontal neocortex membranes of the rat brain. These binding sites are very sensitive to protein-modifying enzymes and reagents such as trypsin and N-ethylmaleimide and to heat denaturation. These results provide direct biochemical evidence for the existence of distinct (d)-NANM-binding sites in rat brain. In addition, this study supports the view that PCP and several of its analogues and the dextrorotatory isomers of psychotomimetic benzomorphans may act at a common recognition site in rat central nervous system.
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PMID:Characterization of specific binding sites for [3H](d)-N-allylnormetazocine in rat brain membranes. 396 30

The effects on oxytocin release of enkephalin analogues, thought to be highly selective agonists of the mu or delta opioid receptor, were compared. Oxytocin release was evoked in urethane-anaesthetised rats (7-10 days post partum) by intracerebroventricular injection of NaCl (3M) at 15-20 min. intervals and detected by the resultant increase in intramammary pressure. Enkephalin analogues (the mu receptor agonist Tyr-D-Ala-Gly-MePhe-NH (CH2)2OH (DAGO), the delta receptor agonist (D-Ala2-D-Leu5) - enkephalin (DADLE) and metkephamid, which has been reported to be particularly efficacious at the delta receptor) were administered intracerebroventricularly 3-5 min. prior to hypertonic saline. Oxytocin release was inhibited in a dose-dependent, naloxone-reversable manner by DAGO (ED50 : 40ng), DADLE (ED50 : 156ng) and metkephamid (ED50 : 42ng); the mammary gland sensitivity to oxytocin was unaffected. These results suggest that the inhibitory action may be mediated through both mu and delta receptors and provide further evidence in support of a role of enkephalins in the control of oxytocin secretion.
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PMID:Inhibition of oxytocin secretion by mu and delta receptor selective enkephalin analogues. 609 11

To investigate the role of multiple opiate receptors in spinal mechanisms of antinociception the activity of various opiate receptor agonists was determined against different nociceptive stimuli in the mouse and rat. Intrathecal administration of the putative kappa-receptor agonists dynorphin A (DYN), bremazocine, and ethylketocyclazocine, as well as the delta-agonist D-Ala2,D-Leu5-enkephalin and the mu-agonists, Tyr-D-Ala-Gly-MePhe-NH-(CH2)2OH and morphine resulted in a dose-dependent antinociceptive effect. The order of potencies was similar for visceral and thermal pain. Inhibition of writhing in mice was much more strongly antagonized by MR 2266 than by naloxone, and des-Tyr1-DYN1-13 was 50 times less potent than DYN in this test suggesting that DYN acts through the kappa-receptor. It is concluded that mu-, delta- and kappa-opiate receptors are involved in spinally mediated antinociception related to kinds of noxious stimuli.
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PMID:Analgesic effects of mu-, delta- and kappa-opiate agonists and, in particular, dynorphin at the spinal level. 614 5

Electrical stimulation (3 Hz, 2 msec duration, 5-12 V for 2 min every 20 min) of cortical slices from the rat, previously incubated with [3H]noradrenaline, evoked a release of tritium which was inhibited by morphine, normorphine, Tyr-D-Ala-Gly-MePhe-NH(CH2) 2OH ( RX783006 ) and D-Ala2-D-Leu5-enkephalin ( pIC30 5.90, 6.32, 7.45 and 6.74 respectively). Naloxone did not affect the release of tritium when given alone but antagonised the actions of the opioids, giving a Ke value of about 3 nM irrespective of the particular agonist used, which suggests an action at mu receptors. The delta opioid receptor blocker, ICI154129 , antagonised the opioids only in large concentrations (Ke 21300 nM). In slices previously incubated with [3H]5-hydroxytryptamine, electrical stimulation increased overflow of tritium but neither naloxone nor the opioid agonists affected evoked overflow of tritium at concentrations which were effective in slices incubated with [3H]noradrenaline. It is concluded that stimulation of mu opioid receptors may inhibit release of noradrenaline from central noradrenergic neurones and that these receptors are not present in significant numbers on neurones releasing 5-hydroxytryptamine in the cortex.
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PMID:Opioid receptor sub-types involved in the control of transmitter release in cortex of the brain of the rat. 614 5

A previous report described the existence of substantial amounts of enkephalin immunoreactivity and the occurrence of nerve terminals containing an enkephalin-like material in the pars nervosa of rat pituitary. It was suggested that an enkephalin innervation of the pars nervosa originating from the magnocellular hypothalamic nuclei might regulate the secretion of neurohypophyseal hormones. The results of the present studies support this hypothesis, as we find that a stable enkephalin analogue (D-Ala 2,D-Leu5-enkephalin) inhibits the calcium-dependent release of vasopressin evoked by electrical stimulation of the rat pituitary stalk in vitro. A similar inhibition of the stimulus-evoked vasopressin release is caused by morphine and beta-endorphin, and the inhibitory effects of the enkephalin analogue can be reversed by naloxone. These findings suggest the possible existence of inhibitory opiate receptors on the terminals of vasopressin fibres in the pars nervosa.
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PMID:Opiate receptors influence vasopressin release from nerve terminals in rat neurohypophysis. 624 3

We have investigated the influence of physico-chemical parameters (chemical structure and lipophilicity), biochemical properties (catabolism, affinity for 3H-etorphine binding sites and 3H-(D-Ala)2-Leu5-enkephalin amide binding sites) and biological activity in isolated organs (guinea-pig ileum and mouse vas deferens) on the regulation of analgesia induced after intracerebroventricular injection of various enkephalin analogs. The selectivity of these metabolically stable analogs for micro- and beta-receptors, present in guinea-pig ileum and mouse vas deferens respectively, depends on the C-terminal amino acid and also on the nature of the second D-amino-acid. A strong correlation exists between activity in guinea-pig ileum and affinity for 3H-etorphine binding sites suggesting that these sites in rat brain have properties identical to those of micro-receptors characterized in guinea-pig ileum. Similarly, the affinity for 3H-(D-Ala)2-Leu5-enkephalin amide binding sites in mouse brain is correlated to the activity in mouse vas deferens and suggests that central beta-receptors are not different from peripheral beta-receptors. If we consider morphine-like drugs and enkephalin analogs containing the same C-terminal amino acid as the enkephalins, there is a good correlation between activity on micro-receptors (affinity for 3H-etorphine binding sites and activity in guinea-pig ileum) and the antinociceptive activity. These results support the hypothesis that micro-receptors are strongly involved in the analgesic effect. However, when proline is the C-terminal amino acid, the antinociceptive activity was enhanced without any concomitant increase in the affinity. This activity enhancement was the same for each analog and a similar correlation (identical to what was found with other opioid peptides and opiates) could still be established. The reason for such a potentiation of the activity remains to be elucidated.
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PMID:Structure-activity relationships of enkephalin analogs at opiate and enkephalin receptors: correlation with analgesia. 624 60

Various opioid receptor agonists, including Met5-enkephalin amide, Leu5-enkephalin amide, [D-Ala]2-Met5-enkephalin amide, [D-Ala]2-Leu5-enkephalin amide, morphine sulfate, d-methadone hydrochloride, and l-methadone hydrochloride were administered to adult male rats by subcutaneous injection. All opioid receptor agonists except Leu5-enkephalin amide significantly stimulated growth hormone and prolactin release. Naloxone and naltrexone blocked the hormone stimulatory effects of the opioids and both naloxone and naltrexone, when administered alone, significantly reduced serum growth hormone and prolactin concentrations. The dopaminergic agonist apomorphine, but not the alpha-adrenergic agonist clonidine, blocked opiate stimulation of prolactin. Morphine sulfate caused growth hormone release in rats pretreated with alpha-methyl-p-tryosine, a catecholamine synthesis inhibitor. Cholinergic agonists, physostigmine and pilocarpine, antagonized the growth hormone and prolactin release induced by morphine sulfate. The data suggest that the opiates stimulate prolactin via an interaction with catecholaminergic neurons controlling prolactin release and stimulate growth hormone via a mechanism independent of alpha-adrenergic or general catecholaminergic influence. The mechanism through which cholinergic agonists act to inhibit opiate agonist stimulation of growth hormone is presently unknown.
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PMID:The effects of opiate agonists on growth hormone and prolactin release in rats. 624 14

1 The action of morphine, naturally occurring and synthetic opiate peptides on [3H]-noradrenaline release induced by nerve stimulation was studied in the isolated nerve muscle preparation of the cat nictitating membrane under experimental conditions in which the alpha-presynaptic receptors were blocked by phentolamine 1 microM. 2 Morphine and the naturally occurring peptides: [Met5]-enkephalin, [Leu5]-enkephalin and beta-endorphin reduced 3H-transmitter overflow and responses to nerve stimulation from the cat nictitating membrane, effects which were completely antagonized by naloxone 0.3 microM. The relative order of potency for the inhibition of the stimulation-induced 3H-transmitter overflow at the level of the IC50 (microM) was as follows: [Met5]-enkephalin (0.020 microM) greater than or equal to [Leu5]-enkephalin (0.036 microM) > morphine (0.3 microM) > beta-endorphin (1 microM). 3 The synthetic opiate pentapeptides: BW 180 C (Tyr-D-Ala-Gly-Phe-D-Leu), and BW834 C (Tyr-D-Ala-Gly-pClPhe-DLeu), which are resistant to enzymatic degradation were more potent than the enkephalins in reducing the stimulation-evoked transmitter overflow from the cat nictitating membrane. On the other hand, the tetrapeptide BW832 C, which lacks the D-leucine terminal of BW180 C l was less potent than the enkephalins in inhibiting neurotransmission. 4 In the presence of phenoxybenzamine 1 microM, 3H-transmitter overflow was increased 8 fold and the inhibition of neurotransmission by methionine-enkephalin was not affected. Exposure to phenoxybenzamine 10 microM increased [3H]-noradrenaline overflow 15 fold and antagonized the effects of methionine enkephalin on transmitter release. 5 In the cat nictitating membrane the inhibitory presynaptic opiate receptors are different from the presynaptic alpha-autoreceptors which regulate the release of noradrenaline elicited by nerve depolarization through a negative feed-back mechanism.
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PMID:Pharmacological differentiation of presynaptic inhibitory alpha-adrenoceptors and opiate receptors in the cat nictitating membrane. 625 97

We have observed two discrete populations of opiate receptors that are differently localized in rat brain. Morphine-like (mu) receptors, labeled by 125I-labeled [D-Ala-2MePhe4Met(O)5-ol]enkephalin, are concentrated selectively in lamina IV of the cerebral cortex, certain thalamic nuclei, and the periaqueductal grey, while delta receptors, labeled by 125I-labeled [D-Ala2-D-Leu5]enkephalin, are more diffused, having high densities in cerebral cortex, corpus striatum, amygdala, and olfactory tubercle. Because of similarities in their localizations, we propose that mu and delta receptors are respectively the physiologic receptors for [Met]- and [Leu]enkephalin neurons. These distributions reflect the different physiological functions attributed to mu and delta receptors and thus represent discrete functions of [Met]- and [Leu]enkephalin neurons.
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PMID:Differentiation of delta and mu opiate receptor localizations by light microscopic autoradiography. 625 83


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