Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.64 (MPP)
 1,876 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of some typical clinically tested psychotropic drugs were studied in acute experiments on awake rats. Potentials in somatosensory cortex were evoked by peripheral stimulation. Haloperidol, diazepam, medazepam, desipramin and a new substance, the MPP-sulton, caused significant modification in latency and amplitude of some components of the potentials. Between the effects of psychotropic drugs exist differences which, in turn, were clearly distinguishable from the modification of these evoked responses by unspecific narcotic effects of hexobarbital.
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PMID:[Effect of psychotropic drugs on somatosensory evoked cortical potentials]. 4 55

The study to an analyse of 726 samples of sea water, taken monthly (1977-1978) at 23 stations. At the basis of the data concerning the NPP of total coliformas, 75,5% of the samples point out a clean water for the bathing place, 11,04% = "acceptable" and 9,96% = "dirty". Considering the data about the MPP of fecal coliformas and of fecal streptocques, the sanitary state is reported in 94,23% "clean for the bathing place", 1,77% "acceptable" and 4% dirty.
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PMID:[Preliminary note on the study of seawater pollution of the Saharan coast of Tunisia]. 12 Oct 49

Pars plana vitrectomy after intraocular foreign body injuries led to a good or at least useful vision in 60% of the cases. Without exception, these were eyes which were practically blind or eyes which according to our experience would have been blinded without vitrectomy. Retinal detachments which have arisen preoperatively have a decisive negative effect on the prognosis: there is a low rate of healing in consequence of traumatic, contusional and metallotic retinal lesions and high MPP rate. Increasing surgical experience, so-called secondary vitrectomy 'in time' as well as improved and more refined vitrectomy instruments lead to better results.
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PMID:Pars plana vitrectomy after intraocular foreign bodies. 54 53

Mean systemic pressure (MSP) and mean pulmonary pressure (MPF), which are mean driving pressures for venous return in the natural heart, were studied in 11 calves in which the natural heart had been replaced with a total artificial heart (TAH). They were measured simply by stopping the artificial heart pumping. Although blood translocation from the arterial to the venous side was not performed, the eventual right and left atrial pressures reached six to eight seconds after stopping the TAH would represent MSP and MPP with reasonable accuracy. The MSP varied from nine to 3k mmHg (20+/-6 mmHg), whereas the MPP varied from nine to 39 mmHg (22+/-7 mmHg). The MSP varied in close relation to the right atrial pressure prior to cessation of the TAH (r=0.9124). Increases in RAP and MSP were mainly attributed to an increase in circulating blood volume. In the performance of the TAH, MSP (or MPP), proper diastolic duration and vacuum application during diastole was of prime importance in determining the end-diastolic ventricular volume.
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PMID:Mean systemic pressure and mean pulmonary pressure: their effects on the total artificial heart. 99 12

In the rat thhe perforant pathways from the entorhinal area normally innervate the fascia dentata only ipsilaterally. However, unilateral ablation of the entorhinal area (deentorhination) induces the formation of an anomalous crossed projection from the intact contralateral entorhinal area to the septal portion of the deafferented fascia dentata. After deentorhination of rats aged 1-30 days the organization of this projection was analyzed (a) by producing secondary lesions in the intact entorhinal area of perforant paths and observing the results anterograde degeneration with Fink-Heimer silver impregnation techniques, and (b) by staining with Timm's sulfide silver method whichmakes the terminal fields of afferent systems stand out in different tones of colors. Both methods showed the crossed entorhino-dentate projection to consist of two separable components. They were named the crossed medial perforant path and the crossed lateral perforant path, corresponding to their similarity in origin, dendritic localization of termination and Timm stainability to the ordinary, uncrossed medial and the lateral perforant pathways (MPP and LPP) which arise in the medial and lateral parts of the entorhinal cortex, respectively. Similarly induced crossed projections were demonstrated to the subcallosal continuation of fascia dentata, the fasciola cinerea. The heaviest terminal field of the crossed entorhino-dentate projection which was found in the most rostral and medial parts of the deafferented fascia dentata correlated with a lack of expected aberrant extension into theMPP and LPP terminal zones of commissural and ipsilateral hippocampodentate fibers. In Fink-Heimer preparations there was little variation in the distribution of the aberrant crossed sustems over the range of ages studied although the chronic operations performed earliest postnatally (5 days) tended to produce the heaviest representation. This latter observation appeared consistent with changes in the Timm staining pattern of the deafferented fascia dentata, since with an increase in age at the primary lesion from 5 to 14 days there was no increase in the spread into the fascia dentata of Timm stainable axon ter minals from CA3, interpreted as a sign of fewer crossed entorhinal afferents succeeding in a presumable competition with the CA3-derived system for available terminal space.
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PMID:Crossed pathways from the entorhinal area to the fascia dentata. II. Provokable in rats. 113 28

N-Methylated beta-carbolinium compounds (N-Me-BCs), including 2-N-methyl and 2,9-N,N-dimethyl analogs, structural analogs of 1-methyl-4-phenylpyridinium (MPP+), may be endogenously bioactivated, MPP(+)-like toxins, capable of inducing parkinsonism. Both MPP+ and selected N-Me-BCs inhibit NADH-linked mitochondrial respiration (Complex I). We now show that both also inhibit succinate-supported (Complex II) respiration, the greatest inhibition (80%) being seen for 2,9-dimethylharmanium. Complex I inhibition occurs at MPP+ concentrations (IC50 = 0.17 mM) about one order of magnitude lower than Complex II inhibition (greater than 1.2 mM). In contrast, Complex I and Complex II inhibition by the N-Me-BCs tested occurred at similar concentrations (I, 0.1 mM; II, 0.25 mM) and concentrations similar to Complex I inhibition by MPP+. 2,9-N,N-Dimethyl-BCs, which are the permanently charged BC analogs of MPP+, show inhibitory characteristics similar to MPP+: slow onset of inhibition, potentiation by TPB, and reversal by DNP. The fact that succinate oxidation cannot bypass the Complex II inhibition by N-Me-BCs could enhance any chronic neurotoxicity of N-Me-BCs.
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PMID:Inhibition of mitochondrial succinate oxidation--similarities and differences between N-methylated beta-carbolines and MPP+. 131 43

A number of nuclearly encoded mitochondrial protein precursors that are transported into the matrix and inner membrane are cleaved in two sequential steps by two distinct matrix peptidases, mitochondrial processing peptidase (MPP) and mitochondrial intermediate peptidase (MIP). We have isolated and purified MIP from rat liver mitochondrial matrix. The enzyme, purified 2250-fold, is a monomer of 75 kDa and cleaves all tested mitochondrial intermediate proteins to their mature forms. About 20% of the final MIP preparation consists of equimolar amounts of two peptides of 47 kDa and 28 kDa, which are apparently the products of a single cleavage of the 75 kDa protein. These peptides are not separable from the 75 kDa protein, nor from each other, under any conditions used in the purification. The peptidase has a broad pH optimum between pH 6.6 and 8.9 and is inactivated by N-ethylmaleimide (NEM) and other sulfhydryl group reagents. The processing activity is divalent cation-dependent; it is stimulated by manganese, magnesium or calcium ions and reversibly inhibited by EDTA. Zinc, cobalt and iron strongly inhibit MIP activity. This pattern of cation dependence and inhibition is not clearly consistent with that of any known family of proteases.
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PMID:Rat liver mitochondrial intermediate peptidase (MIP): purification and initial characterization. 132 90

The major mitochondrial processing activity removing presequences from nuclear encoded precursor proteins is present in the soluble fraction of fungal and mammalian mitochondria. We found that in potato, this activity resides in the inner mitochondrial membrane. Surprisingly, the proteolytic activity co-purifies with cytochrome c reductase, a protein complex of the respiratory chain. The purified complex is bifunctional, as it has the ability to transfer electrons from ubiquinol to cytochrome c and to cleave off the presequences of mitochondrial precursor proteins. In contrast to the nine subunit fungal complex, cytochrome c reductase from potato comprises 10 polypeptides. Protein sequencing of peptides from individual subunits and analysis of corresponding cDNA clones reveals that subunit III of cytochrome c reductase (51 kDa) represents the general mitochondrial processing peptidase.
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PMID:The general mitochondrial processing peptidase from potato is an integral part of cytochrome c reductase of the respiratory chain. 132 69

Using a standard two-lever operant procedure with rats trained to discriminate 1-(3-trifluoromethylphenyl)piperazine (TFMPP) (0.5 mg/kg) from saline, tests of stimulus antagonism and stimulus generalization were performed to better understand the stimulus properties of this agent. The agents examined for ability to antagonize the TFMPP stimulus were prazosin, quipazine, zacopride, buspirone, 8-hydroxy-2-(di-N-propylamino) tetralin (8-OH-DPAT), 1-(2-methoxyphenol)-4-[4-(2-phthalimido)butyl]-piperazine (NAN-190), haloperidol, and 1-(2-pyrimidinyl)piperazine (1-PP); only buspirone attenuated the response to TF-MPP. In separate experiments, the lowest nondisrupting dose of buspirone (1.2 mg/kg) caused a rightward shift of the TFMPP dose-response curve (TFMPP alone, ED50 = 0.19 mg/kg; TFMPP + buspirone, ED50 = 0.43 mg/kg). In addition, 3-(1,2,5,6-tetrahydropyrid-4-yl)pyrrolo[3,2-b]pyrid-5-one (CP 93, 129), 7-trifluoromethyl-4-(4-methyl-1-piperazinyl)pyrolo[1,2-a]quinox ali ne (CGS 12066B), 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), 3-chlorophenylbiguanide (mCPBG), NAN-190, nisoxetine, zacopride, 1-PP, (+)-N-allylnormetazocine ((+)-NANM), and N-methyl-1-(3,4-methylenedioxyphenyl)-2-aminopropane (MDMA) were analyzed in tests of stimulus generalization. The TFMPP stimulus generalized only to CGS 12066B (ED50 = 4.2 mg/kg) and (+)-NANM (ED50 = 8.8 mg/kg). Tests with DOI and MDMA resulted in partial generalization. Up to doses that disrupted behavior, all other agents had little effect on TFMPP-appropriate responding. The results of these and other published studies suggest roles for 5-hydroxytryptamine 1B (5-HT1B), 5-HT1C, and, possibly, sigma-receptors in the mediation of the TFMPP stimulus and indicate a lack of involvement of 5-HT1A, 5-HT2, dopaminergic, and adrenergic mechanisms in this behavior.
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PMID:Mechanistic investigation of the stimulus properties of 1-(3-trifluoromethylphenyl)piperazine. 133 84

The relationship between structural specificity of the main stages of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) action and the display of parkinsonogenic properties among homologous structures in a number of 4-tolyl derivatives of MPTP has been studied. All the compounds are better substrates for monoamine oxidase (MAO) than MPTP. MAO is inactivated during the reaction according to a mechanism of irreversible inhibition by 2,3-dihydropyridinium metabolite. All the tolyl derivatives are stronger inhibitors of MAO than 1-methyl-2,3-dihydropyridinium (MPDP). A significant contribution of enzyme inhibition to the catalytic conversion of the substrate leads to the fact that substrates having equal (para isomer) or even higher (meta isomer) values of catalytic parameters are oxidized by MAO to a lesser extent than MPTP. It has been found that all 4-arylpyridiniums (final products of MATP bioconversion) competitively and reversibly inhibit [14C]dopamine (DA) uptake in mouse brain synaptosomes. Affinity toward DA transporter characterized by KI (microM) is 0.37 +/- 0.04, 0.7 +/- 0.1, 2.0 +/- 0.15, 2.0 +/- 0.35 for MPP, and its o-, m-, and p-tolyl derivatives, respectively. Joint calculation of specificity factors for the processes discussed define the following rank order for the bio-delivery of MATP's metabolic produces into DA nerve terminals: o-tolyl > MPTP >> m-tolyl > p-tolyl. The regularity revealed is in good agreement with the observed relative potency of these compounds to cause dopaminergic neurodegeneration.
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PMID:Molecular basis of discrepancies in neurotoxic properties among 1-methyl-4-aryl-1,2,3,6-tetrahydropyridines. 136 75


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