The effect of β-mercaptoethanol on lactate dehydrogenase from rat brain

Abstract Catalytic studies on lactate dehydrogenase from rat brain in the presence of β-mercaptoethanol have been performed. It has been found that pyruvate reduction and lactate dehydrogenation were differently affected by the addition of the sulfhydryl compound to the reaction mixture. The effect of β-mercaptoethanol on the catalyzed reaction has been shown to be dependent on the hydrogen ion concentration. When lactate dehydrogenation is measured, β-mercaptoethanol causes a net enhancement of the reaction rate at the more acidic pH values.

Interaction Between Uridine and GABA-Mediated Inhibitory Transmission: Studies In Vivo and In Vitro

Na+-independent [3H]gamma-aminobutyric acid (GABA) binding to membrane preparations from frontal cortex, hippocampus, and thalamus is competitively inhibited by the in vitro addition of a naturally occurring pyrimidinic compound, uridine. Moreover, the intraperitoneal injection of uridine produces a dose-related decrease in the cerebellar content of cyclic GMP and antagonizes its increase elicited by bicuculline. The pyrimidinic compound also shows an antagonism toward bicuculline-induced seizures. The relationship between the anti-convulsant actions of uridine and GABA-mediated inhibitory neurotransmission is discussed in terms of an activation of GABA receptor function by the naturally oc…

NEUROPHYSIOLOGICAL AND NEUROCHEMICAL STUDIES WITH THE ISONICOTINOYLHYDRAZONE OF PYRIDOXAL 5-PHOSPHATE.

Interaction of uridine with GABA binding sites in cerebellar membranes of the rat

The effect of uridine, a postulated anticonvulsant agent, on GABA receptors has been investigated. Uridine inhibits [3H]GABA binding to rat cerebellar buffer-washed membranes. Pretreatment of the membranes with Triton X-100 increases the effect of uridine on GABA-binding. The Scatchard analysis reveals that both high and low affinities of GABA for its receptors are affected by 1 mM uridine, while the apparent number of binding sites remains unchanged. The ability of uridine to interact competitively with GABA binding sites, also examined by the Lineweaver-Burk analysis, suggests a possible mechanism of action of this anticonvulsant agent, so including it among those compounds characterized …

Effect of beta-N-oxalylamino-L-alanine on cerebellar cGMP level in vivo.

Beta-N-oxalylamino-L-alanine (BOAA), a non-protein amino acid present in the seeds of Lathyrus Sativus (LS), is one of several neuroactive glutamate analogs reported to stimulate excitatory receptors and, in high concentrations, cause neuronal degeneration. In the present study, the in vivo acute effects of synthetic BOAA and LS seed extract were investigated on rat cerebellar cyclic GMP following intraperitoneal (10-100 mg/kg) or oral (100 mg/kg) administration of subconvulsive doses of toxin. Furthermore, the BOAA content in LS seeds and in the cerebellum of injected rats was determined by high performance liquid chromatograph analysis. A dose- and time-dependent increase of cerebellar cy…

LACTATE-DEHYDROGENASE ISOENZYMES IN NERVOUS TISSUE. II. A COMPARATIVE ANALYSIS IN VERTEBRATES.

Identification of an Antigen Related to the Sea Urchin RNA-Binding Protein LP54 in Mammalian Central Nervous System

LP54 is an RNA-binding protein involved in localization of maternal messengers in sea urchin egg and embryos. Using a polyclonal antibody directed against Paracentrotus lividus LP54 we detected a 66-kDa cross-reacting antigen in undifferentiated and differentiated SH-SY5Y human neuroblastoma cells. After treatment of undifferentiated cells with detergent, the 66-kDa antigen was found to be enriched in the cytoskeletal fraction. By Western blot the expression of this antigen was also analyzed in regions of the CNS and in tissues of the adult rat and its exclusive presence in the hippocampus and thalamus was revealed. The immunoreactivity with P. lividus antibody against LP54 in hippocampal l…

LACTATE DEHYDROGENASE ISOENZYMES IN THE NERVOUS TISSUE?V..

Amino acid transport in the retina.

The uptake, exit, homoexchange, inhibitory pattern, and kinetic analysis of transport of three amino acids were studied in the isolated retina of adult rat under different metabolic conditions. Only in the case of glycine, uptake and exit were shown to duplicate the processes observed in brain slices. In the case of lysine, glucose and oxygen showed an inhibitory effect, but with glutamate spontaneous exit could not be measured. It was also found that the rate of homoexchange for glycine and glutamate, but not for lysine, increases in the presence of oxygen and glucose.

ATPase in the normal and dystrophic developing retina of the rat

Viene descritto un aumento significativo dell'attivita specifica dell'ATPasi (attivita/mg proteine) durante lo sviluppo post-natale della retina in ratti normali ed in ratti con retinite pigmentosa ereditaria. Il rapporto tra attivita ATPasica in presenza di Mg++-Na+-K+ ed attivita ATPasica in presenza di Mg++ non varia nella retina normale, mentre esso va incontro ad un precoce declino durante lo sviluppo della retina distrofica. Il significato di questi dati e discusso molto brevemente.

NAD- and NADP-linked dehydrogenases in the sciatic nerve of rats injected with di-isopropylfluorophosphate.