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Monoamine Oxidase Activity (monoamine + oxidase_activity)
Selected AbstractsMonoamine oxidase activity in kidney and heart of Piaractus mesopotamicus (Holmberg)JOURNAL OF FISH BIOLOGY, Issue 6 2007C. M. C. Salles The values of Michaelis,Menten constant (KM) and maximum velocity (VMAX) for kidney and heart monoamine oxidase (MAO) from pacu Piaractus mesopotamicus were determined. The mean ±s.e. KM values were 17·28 ± 2·27 ,M for kidney and 15·38 ± 1·86 ,M for heart. MAO activities were 111·60 ± 3·25 and 15·12 ± 0·30 nmols min,1 g,1 of wet tissue for kidney and heart, respectively. In addition, MAO inhibitory studies in these two tissues indicate that this enzyme may be a different isoform of MAO. [source] Changes in brain biogenic amines and haem biosynthesis and their response to combined administration of succimers and Centella asiatica in lead poisoned ratsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 4 2006Geetu Saxena This study was designed to investigate the therapeutic potential of meso 2,3-dimercaptosuccinic acid (DMSA) and one of its monoesters, monoisoamyl DMSA (MiADMSA), individually or when administered in combination with an extract of Centella asiatica against experimental lead intoxication in rats. Biochemical variables indicative of alterations in the central nervous system and haem biosynthesis were investigated to determine the toxicity in male Wistar rats. Thirty five rats were exposed to 0.2% lead acetate for 10 weeks, followed by 10 days of treatment with DMSA and MiADMSA (50 mg kg,1, i.p., once daily) alone and in combination with C. asiatica (200 mg kg,1, p.o., once daily). Biochemical variables indicative of oxidative stress and brain biogenic amines, along with lead concentration in blood and brain, were measured. Lead exposure caused a significant depletion of blood and brain ,-aminolevulinic acid dehydratase (ALAD) activity, an important enzyme of the haem biosynthesis pathway, and glutathione (GSH) level. These changes were accompanied by a marked increase in reactive oxygen species (ROS) level, thiobarbituric acid reactive substances (TBARS), ,-aminolevulinic acid synthase (ALAS) and oxidized glutathione (GSSG) activity in blood and brain. Significant depletion of brain noradrenaline (norepinephrine, NE), 5-hydroxytryptamine (5-HT), dopamine (DA) and acetylcholinesterase (AChE) also were observed following lead exposure. Also seen was a significant depletion in brain glutathione peroxidase (GPx), glutathione S-transferase (GST) and monoamine oxidase activity, as well as blood and brain superoxide dismutase (SOD) activity. These biochemical changes were correlated with an increased uptake of lead in blood and brain. Combined administration of MiADMSA and C. asiatica was most effective in reducing these alterations, including biogenic amines, besides reducing body lead burden, compared with individual treatment with MiADMSA. Certain other biochemical variables responded favourably to combination therapy and monotherapy with MiADMSA. Thus, supplementation of C. asiatica during chelation could be recommended for achieving optimum effects of chelation therapy. [source] Effect of a Photo-synthetic Inhibitor on Tryptamine Pathway-mediated Sekiguchi Lesion Formation in Lesion Mimic Mutant of Rice Infected with Magnaporthe griseaJOURNAL OF PHYTOPATHOLOGY, Issue 9 2008A. Imaoka Abstract A lesion-mimic mutant of rice (cv. Sekiguchi-asahi) showed enhanced resistance to Magnaporthe grisea infection, thereby inducing Sekiguchi lesion (sl) formation and tryptamine accumulation under light. Both Sekiguchi lesion formation and tryptamine accumulation in leaves infected with M. grisea were inhibited by pretreatment with the photosynthetic inhibitor, 3-(3, 4-Dichlorophenyl)-1,1-dimethylurea (DCMU), which suppressed the gene expression of tryptophan decarboxylase (TDC), monoamine oxidase activity, H2O2 generation and DNA fragmentation. Catalase activity was inhibited by M. grisea infection under light, but magnitude of the inhibition was reduced in leaves pretreated with DCMU. Furthermore, tryptophan accumulated in M. grisea- infected leaves under light but not in DCMU-pretreated ones. Interestingly, such DCMU inhibition was reduced in the presence of tryptophan. Our studies suggest that chloroplasts function as the inhibitor of anti-oxidant system such as catalase activity and the supplier of a precursor of tryptamine and tryptophan in the sl mutant infected with M. grisea. [source] Catecholamine synthesis and metabolism in the central nervous system of mice lacking ,2 -adrenoceptor subtypesBRITISH JOURNAL OF PHARMACOLOGY, Issue 3 2009MA Vieira-Coelho Background and purpose:, This study investigates the role of ,2 -adrenoceptor subtypes, ,2A, ,2B and ,2C, on catecholamine synthesis and catabolism in the central nervous system of mice. Experimental approach:, Activities of the main catecholamine synthetic and catabolic enzymes were determined in whole brains obtained from ,2A -, ,2B - and ,2C -adrenoceptor knockout (KO) and C56Bl\7 wild-type (WT) mice. Key results:, Although no significant differences were found in tyrosine hydroxylase activity and expression, brain tissue levels of 3,4-dihydroxyphenylalanine were threefold higher in ,2A - and ,2C -adrenoceptor KO mice. Brain tissue levels of dopamine and noradrenaline were significantly higher in ,2A and ,2CKOs compared with WT [WT: 2.8 ± 0.5, 1.1 ± 0.1; ,2AKO: 6.9 ± 0.7, 1.9 ± 0.1; ,2BKO: 2.3 ± 0.2, 1.0 ± 0.1; ,2CKO: 4.6 ± 0.8, 1.5 ± 0.2 nmol·(g tissue),1, for dopamine and noradrenaline respectively]. Aromatic L-amino acid decarboxylase activity was significantly higher in ,2A and ,2CKO [WT: 40 ± 1; ,2A: 77 ± 2; ,2B: 40 ± 1; ,2C: 50 ± 1, maximum velocity (Vmax) in nmol·(mg protein),1·h,1], but no significant differences were found in dopamine ,-hydroxylase. Of the catabolic enzymes, catechol- O -methyltransferase enzyme activity was significantly higher in all three ,2KO mice [WT: 2.0 ± 0.0; ,2A: 2.4 ± 0.1; ,2B: 2.2 ± 0.0; ,2C: 2.2 ± 0.0 nmol·(mg protein),1·h,1], but no significant differences were found in monoamine oxidase activity between all ,2KOs and WT mice. Conclusions and implications:, In mouse brain, deletion of ,2A - or ,2C -adrenoceptors increased cerebral aromatic L-amino acid decarboxylase activity and catecholamine tissue levels. Deletion of any ,2 -adrenoceptor subtypes resulted in increased activity of catechol- O -methyltransferase. Higher 3,4-dihydroxyphenylalanine tissue levels in ,2A and ,2CKO mice could be explained by increased 3,4-dihydroxyphenylalanine transport. [source] | ||||||||||