Susana Pereyra-Alfonso

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Several ontogenetic studies have been devoted to the structural organization of the developing tectum opticum. They disagree in many respects because they are based on histological preparations performed with differently oriented planes of section. According to our results the differences found in the literature mainly result from the fact that the(More)
Plasminogen activator (PA) activity was studied in a transplantable murine mammary adenocarcinoma (M3), moderately metastatic to lungs, and in a highly metastatic variant tumor (MM3) to establish whether a correlation existed between this enzyme and the tumors' metastasizing abilities. The cell-associated and secreted PA activities from primary cultures of(More)
Angiotensin (Ang)-(1-7) is an endogenous peptide hormone of the renin-angiotensin system which exerts diverse biological actions, some of them counterregulate Ang II effects. In the present study potential effect of Ang-(1-7) on phosphoinositide (PI) turnover was evaluated in neonatal rat brain. Cerebral cortex prisms of seven-day-old rats were preloaded(More)
Ontogenetic studies indicate that inositol phosphate accumulation in rodent brain tissue by cholinergic muscarinic agonists as well as expression of high-affinity neurotensin receptor (NTS1) peak at 7 days after birth. Herein, potential participation of this receptor in such effect was investigated. Cerebral cortex prisms of 7-day-old rats were preloaded(More)
The developing mesencephalic trigeminal nucleus (nucleus of the fifth cranial nerve; Mes5) is composed of four neuron populations: 1) the medial group, located at the tectal commissure; 2) the lateral group distributed along the optic tectum hemispheres; 3) a group outside the neural tube; and 4) a population located at the posterior commissure. The present(More)
Plasminogen activators are considered to be involved in several developmental events. The present work aims at characterizing the developmental pattern of expression of plasminogen activators in the chick cerebellum. Soluble fractions derived by ultracentrifugation from Triton X-100 treated membrane fractions were used for determination of the enzyme(More)
A quantitative ultrastructural evaluation of the oocyte ribosomal population was carried out during the oocyte growth, bearing in mind that this period of the mouse oogenesis displays the greatest activity of ribosomal RNA synthesis. At the onset of growth almost 3/4 of the oocyte ribosomes exist as singles, these become polysomal ribosomes as growth(More)
Phosphoinositide (PI) metabolism is enhanced in neonatal brain by activation of neurotransmitter receptors and by inhibition of the sodium pump with ouabain or endogenous inhibitor termed endobain E. Peptide neurotensin inhibits synaptosomal membrane Na+, K+-ATPase activity, an effect blocked by SR 48692, a selective antagonist for high-affinity neurotensin(More)
Plasminogen activators are serine proteases which play a key role in morphogenesis and tissue remodelling. Two different molecular types, tissue-type and urokinase-type, were identified and they were postulated to play a role in neural development. The developing chick optic lobe plays a central role in processing visual information. In previous studies we(More)