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R Guarneri

Publications and source records attributed to R Guarneri.

36 records · Page 2Linked to original sources
PubMed1983

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 by a GABAergic agonist activity.

Animals↗
PubMed1978

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.

Amino Acids↗
PubMedDate not supplied

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 occurring pyrimidinic compound.

Animals↗
PubMedDate not supplied

New insights on the pathogenesis of neurodegenerative disorders.

In the last few years, an increasing amount of studies have been dedicated to the etiopathogenesis of age-related neurodegenerative disorders, such as Parkinson's disease, amyotrophic lateral sclerosis and Alzheimer's disease. The discovery of synthetic, as well as natural molecules, able to reproduce in the animals biochemical and morphological alterations of neurodegenerative disorders, has provided a major impetus to the "environmental" hypothesis of neurodegeneration. In this review, following a brief description of the ability of the nervous system to counteract the degenerative process, the main neurotoxic-based animal models for neurodegeneration are examined. These might give us interesting clues for understanding the pathogenetic mechanism(s) of neurodegenerative process.

Animals↗
PubMedDate not supplied

[Enzymatic study of peripheral nervous tissue and the retinas of rats subjected to experimental hyperglycemia: effect of ganglioside administration].

The authors submitted to alloxan hyperglycemia albino rats of the Wistar strain. Alloxan is a sulphydryl poison, characterized by its selective action on the beta-cells of the islets of Langerhans. Rats were partly treated with a mixture of gangliosides both for 10 days before hyperglycemia induction and during the following experimental period. Treatment with gangliosides caused in both groups a precocious and significant normalization of metabolic variation seen in hyperglycemic non treated rats. The Authors discuss the physiopathologic significance of the enzymatic variations found in two nervous structures, retina and sciatic nerve, in which initial diabetes-like condition has been induced. Gangliosides, whose use is warranted by recent studies about their effect in cell membrane function, seem to suggest, in this case, a preeminent metabolic action, also if their role is still not completely clear.

Adenosine Triphosphate↗