The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Alfredo Argiolas - One of the best experts on this subject based on the ideXlab platform.
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EP 60761- and EP 50885-induced penile erection: structure-activity studies and comparison with apomorphine, oxytocin and N-methyl-D-Aspartic Acid
International Journal of Impotence Research, 2000Co-Authors: Maria Rosaria Melis, Succu S, Locatelli, Antonio Torsello, Eugenio E. Müller, Romano Deghenghi, Maria Sabrina Spano, Alfredo ArgiolasAbstract:EP 60761- and EP 50885-induced penile erection: structure–activity studies and comparison with apomorphine, oxytocin and N -methyl- D -aspartic Acid
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EP 60761- and EP 50885-induced penile erection: structure–activity studies and comparison with apomorphine, oxytocin and N-methyl-D-Aspartic Acid
International Journal of Impotence Research, 2000Co-Authors: M R Melis, S Succu, Antonio Torsello, Romano Deghenghi, Ms Spano, V Locatelli, Ee Muller, Alfredo ArgiolasAbstract:The effect of 10 peptides structurally related to the growth hormone (GH) releasing peptide hexarelin, injected into the paraventricular nucleus of the hypothalamus (PVN), on penile erection was studied in male rats. Six out of the 10 peptides tested induced penile erection in a dose-dependent manner. Among them, the most potent were EP 80661, EP 60761 and EP 91072, which were active at doses of 20–200 ng. The potency of these peptides in inducing penile erection is comparable to that of apomorphine, oxytocin and N -methyl- D -aspartic Acid similarly injected into the PVN. Other peptides found active were EP 50885, EP 90101 and EP 91071, which induced penile erection at doses of 200–2000 ng. In contrast, EP 51322, EP 70555, EP 51216 and EP 91073 were inactive, as were hexarelin, EP 40904 and EP 40737 in a previous study. The majority of EP peptides found active when injected into the PVN induced penile erection, although to a lesser extent, also when given systemically (endovenously). The proerectile effect of EP peptides was prevented by the oxytocin receptor antagonist [d(CH_2)_5 Tyr(Me)^2-Orn^8]-vasotocin given into the lateral ventricles but not into the PVN, by the nitric oxide (NO) synthase inhibitor N^G-nitro-l-arginine methyl ester given either into the lateral ventricles or into the PVN, by the N -type Ca^2+ channel blocker ω-conotoxin GVIA and by morphine, but not by the dopamine receptor antagonist cis -flupenthixol or by the N -methyl- D -aspartic Acid receptor antagonist dizolcipine, given into the PVN. As the structure–activity relationship of EP peptides for proerectile activity is different from those of other biological actions of these compounds, ie for GH release and eating behaviour, the present results suggest that EP peptides induce penile erection by acting on specific hypothalamic receptor sites that activate paraventricular oxytocinergic neurons projecting to extrahypothalamic brain areas that mediate this sexual function by a mechanism similar to that of dopamine receptor agonists, oxytocin and N -methyl- D -aspartic Acid.
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N-methyl-D-Aspartic Acid-induced penile erection and yawning: role of hypothalamic paraventricular nitric oxide.
European journal of pharmacology, 1997Co-Authors: M R Melis, S Succu, U Iannucci, Alfredo ArgiolasAbstract:A dose of N-methyl-D-Aspartic Acid (NMDA, 50 ng) that induces penile erection and yawning when injected into the paraventricular nucleus of the hypothalamus, increased the concentration of NO2- from 1.10 +/- 0.28 microM to 7.32 +/- 1.12 microM and of NO3 from 4.96 +/- 0.69 microM to 10.5 +/- 1.61 microM in the paraventricular dialysate obtained from male rats by in vivo microdialysis. NO2- concentration was not increased by (+/-)-alpha-(amino)-3-hydroxy-5-methylisoxazole-4-propionic Acid (AMPA, 100 ng) or by trans-(+/-)-1-amino-1,3-cyclopentanedicarboxylic Acid (ACPD) (100 ng), which were unable to induce these behavioral responses. N-Methyl-D-Aspartic Acid effect on NO2- concentration, penile erection and yawning was prevented by dizolcipine (MK-801) (10-100 ng) or by the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (20 microg), but not by the oxytocin receptor antagonist [d(CH2)5,Tyr(Me)2,Orn8]vasotocin (100 ng), or by the guanylate cyclase inhibitor methylene blue (20 microg) given in the paraventricular nucleus 15 min before N-methyl-D-Aspartic Acid or by the dopamine receptor antagonist haloperidol (0.5 mg/kg) given intraperitoneally 30 min before N-methyl-D-Aspartic Acid. In contrast, the nitric oxide scavenger hemoglobin (20 microg) given in the paraventricular nucleus prevented N-methyl-D-Aspartic Acid-induced NO2- concentration increase, but was unable to prevent penile erection and yawning. The results suggest that N-methyl-D-Aspartic Acid induces penile erection and yawning by increasing nitric oxide synthase activity in the paraventricular nucleus of the hypothalamus, possibly in the cell bodies of oxytocinergic neurons projecting to extra-hypothalamic brain areas and mediating these behavioral responses.
Antimo D'aniello - One of the best experts on this subject based on the ideXlab platform.
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D-Aspartic Acid is a novel endogenous neurotransmitter
FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 2010Co-Authors: Salvatore D'aniello, Enza Topo, Jordi Garcia-fernàndez, Ildiko M. L. Somorjai, Antimo D'anielloAbstract:D-Aspartic Acid (D-Asp) is present in invertebrate and vertebrate neuroendocrine tissues, where it carries out important physiological functions and is implicated in nervous system development. We show here that D-Asp is a novel endogenous neurotransmitter in two distantly related animals, a mammal (Rattus norvegicus) and a mollusk (Loligo vulgaris). Our main findings demonstrate that D-Asp is present in high concentrations in the synaptic vesicles of axon terminals; synthesis for this amino Acid occurs in neurons by conversion of L-Asp to D-Asp via D-aspartate racemase; depolarization of nerve endings with K+ ions evokes an immediate release of D-Asp in a Ca2+ dependent manner; specific receptors for D-Asp occur at the postsynaptic membrane, as demonstrated by binding assays and by the expansion of squid skin chromatophores; d-aspartate oxidase, the specific enzyme that oxidizes D-Asp, is present in the postsynaptic membranes; and stimulation of nerve endings with D-Asp triggers signal transduction by in...
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Evidence for the involvement of D-Aspartic Acid in learning and memory of rat
Amino Acids, 2009Co-Authors: Enza Topo, Angela Di Maio, Enrico D'aniello, Maria Maddalena Di Fiore, Andrea Soricelli, Antimo D'anielloAbstract:D-Aspartic Acid (d-Asp) is an endogenous amino Acid present in neuroendocrine systems. Here, we report evidence that d-Asp in the rat is involved in learning and memory processes. Oral administration of sodium d-aspartate (40 mM) for 12–16 days improved the rats’ cognitive capability to find a hidden platform in the Morris water maze system. Two sessions per day for three consecutive days were performed in two groups of 12 rats. One group was treated with Na-d-aspartate and the other with control. A significant increase in the cognitive effect was observed in the treated group compared to controls (two-way ANOVA with repeated measurements: F(2, 105) = 57.29; P value < 0.001). Five further sessions of repeated training, involving a change in platform location, also displayed a significant treatment effect [F(2, 84) = 27.62; P value < 0.001]. In the hippocampus of treated rats, d-Asp increased by about 2.7-fold compared to controls (82.5 ± 10.0 vs. the 30.6 ± 5.4 ng/g tissue; P < 0.0001). Moreover, 20 randomly selected rats possessing relatively high endogenous concentrations of d-Asp in the hippocampus were much faster in reaching the hidden platform, an event suggesting that their enhanced cognitive capability was functionally related to the high levels of d-Asp. The correlation coefficient calculated in the 20 rats was R = −0.916 with a df of 18; P < 0.001. In conclusion, this study provides corroborating evidence that D-Aspartic Acid plays an important role in the modulation of learning and memory.
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N-methyl-D-Aspartic Acid (NMDA) in the nervous system of the amphioxus Branchiostoma lanceolatum.
BMC Neuroscience, 2007Co-Authors: Salvatore D'aniello, George Fisher, Enza Topo, Gabriele Ferrandino, Jordi Garcia-fernàndez, Antimo D'anielloAbstract:Background NMDA (N-methyl-D-Aspartic Acid) is a widely known agonist for a class of glutamate receptors, the NMDA type. Synthetic NMDA elicits very strong activity for the induction of hypothalamic factors and hypophyseal hormones in mammals. Moreover, endogenous NMDA has been found in rat, where it has a role in the induction of GnRH (Gonadotropin Releasing Hormone) in the hypothalamus, and of LH (Luteinizing Hormone) and PRL (Prolactin) in the pituitary gland.
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A physiological mechanism to regulate D-Aspartic Acid and NMDA levels in mammals revealed by D-aspartate oxidase deficient mice.
Gene, 2006Co-Authors: Francesco Errico, Antimo D'aniello, Patrizia Spinelli, Maria Teresa Pirro, Andrea Affuso, Mario De Felice, Roberto Di LauroAbstract:Free D-Aspartic Acid and NMDA are present in the mammalian central nervous system and endocrine glands at significant concentrations, but their physiological role is still matter of debate. The only enzyme known to metabolize in vitro selectively these D-amino Acids is D-aspartate oxidase (DDO). To clarify the role in vivo of the enzyme, we generated mice with targeted deletion of Ddo gene by homologous recombination. Mutated animals showed increased amounts of both D-Aspartic Acid and NMDA in all tissues examined demonstrating a physiological role of DDO in the regulation of their endogenous levels.
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Occurrence of D-Aspartic Acid in human seminal plasma and spermatozoa: possible role in reproduction.
Fertility and sterility, 2005Co-Authors: Gemma D'aniello, Patrizia Spinelli, Salvatore Ronsini, Francesco Guida, Antimo D'anielloAbstract:Objective To determine D-Aspartic Acid (D-Asp) in human seminal plasma and spermatozoa in fertile and infertile donors. Design Prospective observation study. Setting Department of Pathophysiology for Human Reproduction, Hospital "S. Luca," Salerno, Italy, and Department of Neurobiology and Comparative Physiology, Zoological Station "A. Dohrn," Naples, Italy. Patient(s) Ten normospermic, 10 oligoasthenoteratospermic, and 10 azoospermic (nonobstructive) men. Intervention(s) D-Aspartic Acid was determined by a specific enzymatic high-performance liquid chromatography method on purified seminal plasma and on isolated spermatozoa and by an immunohistochemical method using light and electronic microscopic techniques. Main Outcome Measure(s) Concentration of D-Asp in seminal plasma and in isolated spermatozoa; subcellular localization of D-Asp in the acrosome and nucleus. Result(s) The concentration of D-Asp in seminal plasma and in spermatozoa was significantly reduced in oligoasthenoteratospermic donors. In the seminal fluid of normospermic donors, D-Asp occurs at a concentration of 80 ± 12 nmol/mL semen (10.4 ± 1.5 μg/mL), whereas 26 ± 6 nmol/mL semen were found in oligoasthenoteratospermic donors, and 12 ± 1.5 nmol/mL semen were found in azoospermic donors. In spermatozoa from normospermic donors, D-Asp occurred at a concentration of 130 ±15 fmol per spermatozoa (17.0 ± 1.96 ng per spermatozoa), vs. 60.5 ± 5.0 fmol per spermatozoa from oligoasthenoteratospermic subjects. Other D-amino Acids analyzed were not present in seminal plasma or in spermatozoa in a significant concentration compared with D-Asp. Conclusion(s) D-Aspartic Acid occurs in human seminal plasma and spermatozoa and is implicated in male fertility.
Luigi Casella - One of the best experts on this subject based on the ideXlab platform.
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Electron paramagnetic resonance studies on VO(IV)-D-Aspartic Acid and VO(IV)-D-Aspartic Acid α-benzylester complexes
Journal of Inorganic Biochemistry, 2001Co-Authors: Rosa Pia Ferrari, Sonia Poli, Enzo Laurenti, Luigi CasellaAbstract:A detailed electron paramagnetic study has been done on oxovanadium(IV)-D-Aspartic Acid and oxovanadium(IV)-D-Aspartic Acid α-benzylester complexes, molar ratio 1:1 and 1:2 in the physiological pH range. Their isotropic and anisotropic spin Hamiltonian parameters have been calculated to second order and the superimposed mixed species spectral patterns have been simulated. The complexes display an approximate C4v geometry whose relative hyperfine coupling constant values are connected with the ligand field strength on the equatorial plane. Furthermore it seems that aspartic Acid, in some circumstances, binds oxovanadium(IV) acting as tridentate ligand, and aspartic Acid α-benzylester can coordinate the metal-ion giving complexes with six-membered chelate rings (α-NH2/β-COO− donor groups). Our EPR results are in agreement with those of UV-visible and CD spectral measurements.
Paul W. M Marshall - One of the best experts on this subject based on the ideXlab platform.
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The effects of D-Aspartic Acid supplementation in resistance-trained men over a three month training period: A randomised controlled trial.
PloS one, 2017Co-Authors: Geoffrey W Melville, Jason C. Siegler, Paul W. M MarshallAbstract:Context Research on D-Aspartic Acid (DAA) has demonstrated increases in total testosterone levels in untrained men, however research in resistance-trained men demonstrated no changes, and reductions in testosterone levels. The long-term consequences of DAA in a resistance trained population are currently unknown. Objective To evaluate the effectiveness of DAA to alter basal testosterone levels over 3 months of resistance training in resistance-trained men. Design Randomised, double-blind, placebo controlled trial in healthy resistance-trained men, aged 18–36, had been performing regular resistance training exercise for at least 3 d.w-1 for the previous 2 years. Randomised participants were 22 men (D-Aspartic Acid n = 11; placebo n = 11) (age, 23.8±4.9 y, training age, 3.2±1.5 y). Intervention D-Aspartic Acid (6 g.d-1, DAA) versus equal-weight, visually-matched placebo (PLA). All participants performed 12 weeks of supervised, periodised resistance training (4 d.w-1), with a program focusing on all muscle groups. Measures Basal hormones, total testosterone (TT), free testosterone (FT), estradiol (E2), sex-hormone-binding globulin (SHBG) and albumin (ALB); isometric strength; calf muscle cross-sectional area (CSA); calf muscle thickness; quadriceps muscle CSA; quadriceps muscle thickness; evoked V-wave and H-reflexes, were assessed at weeks zero (T1), after six weeks (T2) and after 12 weeks (T3). Results No change in basal TT or FT were observed after the intervention. DAA supplementation (n = 10) led to a 16%, 95% CI [-27%, -5%] reduction in E2 from T1-T3 (p
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Three and six grams supplementation of D-Aspartic Acid in resistance trained men
Journal of the International Society of Sports Nutrition, 2015Co-Authors: Geoffrey W Melville, Jason C. Siegler, Paul W. M MarshallAbstract:Background Although abundant research has investigated the hormonal effects of D-Aspartic Acid in rat models, to date there is limited research on humans. Previous research has demonstrated increased total testosterone levels in sedentary men and no significant changes in hormonal levels in resistance trained men. It was hypothesised that a higher dosage may be required for experienced lifters, thus this study investigated the effects of two different dosages of D-Aspartic Acid on basal hormonal levels in resistance trained men and explored responsiveness to D-Aspartic Acid based on initial testosterone levels.
Michajlovskij N - One of the best experts on this subject based on the ideXlab platform.
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N-methyl-D-Aspartic Acid injected peripherally stimulates oxytocin and vasopressin release.
Endocrine Regulations, 1992Co-Authors: Daniela Jezova, Michajlovskij NAbstract:: The effects of N-methyl-D-Aspartic Acid (NMDA), injected s.c. or i.p. in the dose range of 2.5-10 mg/kg, on oxytocin and vasopressin levels were assessed in conscious rats. NMDA administration was found to induce a dose-related increase in oxytocin concentration with a peak response at 7.5 min. Plasma vasopressin was elevated only after injection of the highest dose used (10 mg/kg). Thus, though at different thresholds, the release of both posterior pituitary hormones was stimulated after NMDA administration.