Biomedical subjects

M T Muiño Blanco

Publications and source records attributed to M T Muiño Blanco.

4 recordsLinked to original sources

PubMed1991

Subfractions of membranes from calf brain synaptosomes obtained and studied by liquid-liquid partitioning.

Synaptosomes isolated from calf brain cortex were lysed and fragmented by Yeda press treatment. The obtained membranes have previously been fractionated in a counter-current distribution process using a liquid-liquid two-phase system consisting of water, dextran, Ficoll and poly(ethylene glycol) [J. Chromatogr., 358 (1986) 147]. Using the fact that there are discrete membrane populations, a rapid preparative method for isolation of the two main fractions is presented in the present work, as well as a subfractionation of one of them using liquid-liquid extraction with dextran-bound Procion yellow HE-3G. The content of several membrane constituents, i.e. protein, acetylcholinesterase, succinate dehydrogenase and ATPase, as well as opiate binding, were determined for the three fractions. Counter-current distribution of the fractions elucidates their heterogeneity and the effectiveness of the purification.

Acetylcholinesterase↗

PubMed1991

Heterogeneity of synaptosomal membrane preparations from different regions of calf brain studied by partitioning and counter-current distribution.

1. Membranes obtained by lysis and Yeda-press treatment of synaptosomes (nerve endings) from cortex, caudateus nucleus, and hippocampal region of calf brain have been studied by partitioning within a liquid-liquid aqueous two-phase system consisting of water, dextran, Ficoll, and poly(ethylene glycol). 2. The partitioning of membranes was sensitive to the presence of a dextran-bound dye, Procion yellow HE-3G, in the lower phase. 3. The two-phase system was used for counter-current distribution to study the heterogeneity of the synaptic membranes from the three regions of the brain and to separate the membranes into fractions. 4. The obtained counter-current distribution profiles strongly depended on the region of the brain from which the membranes were isolated. 5. The membrane fractions obtained showed marked differences in their SDS electrophoresis pattern.

Animals↗

PubMed1990

Rat brain synaptosomes prepared by phase partition.

Synaptosomes from rat forebrain can easily be isolated by combining centrifugation with partition in an aqueous two-phase system composed of dextran T500 and polyethylene glycol 4000 in which synaptosomes have an extreme affinity for the upper phase. The fraction thus obtained has been characterized by electron microscopy and biochemical markers for synaptosomes and some other cell components. The contamination by microsomes, free mitochondria, and myelin was 4.4, 3.2, and 0.1%, respectively. The morphometric analysis of the electron micrographs shows that greater than 60% of the structures are synaptosomes. This preparation of the isolation procedure is remarkably short (less than 1 h), formance as assayed by their respiratory activities and ATP level in the absence and presence of depolarizing agents. Synaptosomes prepared by phase partition release the neurotransmitter glutamate in a Ca2(+)-dependent manner. The duration of the isolation procedure is remarkably short (less than 1 h), no ultracentrifuge is required, and the method can be applied for small- or large-scale preparations.

Adenosine Diphosphate↗

PubMed1986

Effect of dextran- and poly(ethylene glycol)-bound procion yellow HE-3G on the partition of membranes from calf brain synaptosomes within an aqueous two-phase system.

Membranes obtained by lysis and Yeda-press treatment of synaptosomes (nerve endings) from calf brain cortex have been partitioned within the aqueous phases (and the interface between them) of a Ficoll-dextran-poly(ethylene glycol)-water two-phase system. By introducing the dye Procion yellow HE-3G in the upper phase, bound to poly(ethylene glycol), or in the lower phase, bound to dextran, the partition of the membranes could be strongly affected. The influence on the partition was more pronounced when the dye was bound to dextran. By using a number of two-phase systems in a counter-current distribution process, it was shown that the membrane preparation was inhomogeneous and that the fractions obtained differed in their contents of acetylcholinesterase, succinate dehydrogenase and ATPase. The affinity partitioning effect depended strongly on the concentration of polymer-bound dye. An optimum dye concentration was found when Procion yellow HE-3G was bound to poly(ethylene glycol). When the same dye was bound to dextran, the number of dye molecules per dextran molecule influenced the effectiveness of the extraction.

Acetylcholinesterase↗