Convulsant bicuculline modifies CNS muscarinic receptor affinity

BACKGROUND: Previous work from this laboratory has shown that the administration of the convulsant drug 3-mercaptopropionic acid (MP), a GAD inhibitor, modifies not only GABA synthesis but also binding of the antagonist [(3)H]-quinuclidinyl benzilate ([(3)H]-QNB) to central muscarinic receptors, an effect due to an increase in affinity without modifications in binding site number. The cholinergic system has been implicated in several experimental epilepsy models and the ability of acetylcholine to regulate neuronal excitability in the neocortex is well known. To study the potential relationship between GABAergic and cholinergic systems with seizure activity, we analyzed the muscarinic receptor after inducing seizure by bicuculline (BIC), known to antagonize the GABA-A postsynaptic receptor subtype. RESULTS: We analyzed binding of muscarinic antagonist [(3)H]-QNB to rat CNS membranes after i.p. administration of BIC at subconvulsant (1.0 mg/kg) and convulsant (7.5 mg/kg) doses. Subconvulsant BIC dose failed to develop seizures but produced binding alteration in the cerebellum and hippocampus with roughly 40% increase and 10% decrease, respectively. After convulsant BIC dose, which invariably led to generalized tonic-clonic seizures, binding increased 36% and 15% to cerebellar and striatal membranes respectively, but decreased 12% to hippocampal membranes. Kd value was accordingly modified: with the subconvulsant dose it decreased 27% in cerebellum whereas it increased 61% in hippocampus; with the convulsant dose, Kd value decreased 33% in cerebellum but increased 85% in hippocampus. No change in receptor number site was found, and Hill number was invariably close to unity. CONCLUSION: Results indicate dissimilar central nervous system area susceptibility of muscarinic receptor to BIC. Ligand binding was modified not only by a convulsant BIC dose but also by a subconvulsant dose, indicating that changes are not attributable to the seizure process itself. Findings support the notion that the muscarinic receptors play a major role in experimental epilepsy and provide a new example of differential neuronal plasticity

An endogenous Na+, K+-ATPase inhibitor enhances phosphoinositide hydrolysis in neonatal but not in adult rat brain cortex

The effect of an endogenous Na+, K+-ATPase inhibitor, termed endobain E, on phosphoinositide hydrolysis was studied in rat brain cortical prisms and compared with that of ouabain. As already shown for ouabain, a transient effect was obtained with endobain E; maximal accumulation of inositol phosphates induced by endobain E was 604 ± 138% and 186 ± 48% of basal values in neonatal and adult rats, respectively. The concentration-response plot for the interaction between endobain E and phosphoinositide turnover differed from that of ouabain, thus suggesting the involvement of distinct mechanisms. In the presence of endobain E plus ouabain at saturating concentrations, no additive effect was recorded, suggesting that both substances share at least a common step in their activation mechanism of inositol phosphates metabolism or that they enhance phosphatidylinositol 4,5-biphosphate breakdown from the same membrane precursor pool, until its exhaustion. Experiments with benzamil, a potent blocker of Na+/Ca2+ exchanger, showed that it partially and dose-dependently inhibited endobain E effect. These results indicate that the endogenous Na+, K+-ATPase inhibitor endobain E, like ouabain, is able to stimulate phosphoinositide turnover transiently during postnatal brain development.Fil: Calviño, Maria Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Peña, Carina Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: De Lores Arnaiz, G. Rodríguez. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; Argentin

Exploring the powerful phytoarsenal of white grape marc against bacteria and parasites causing significant diseases

Natural extracts containing high polyphenolic concentration possess antibacterial, antiparasitic and fungicidal activities. The present research characterises white grape marc, a winemaking by-product describing their physicochemical features and antimicrobial capacities. Main components of 2 different extracts generated were phenolic acids, flavan-3-ols and their gallates, and flavonols and their glycosides. As a result of this complex composition white grape marc extracts showed pronounced bioactivities with potential uses in agricultural, pharmaceutical and cosmetic industries, among others. Specifically, polyphenol compounds were extracted by using hydro-organic solvent mixtures from the by-product of Albariño white wines (Galicia, NW Spain) production. In the present work the “in vitro” antimicrobial activity of the bioactive extracts was evaluated using two different hydro-organic mixtures (HOL & HOP). The microorganisms tested included Gram positive and negative bacteria, two Apicomplexan parasite species and one Oomycota parasite. Microbial species investigated are causing agents of several human and animal diseases, such as foodborne illnesses (Bacillus cereus, Eschericha coli, Salmonella enterica), skin infections (Staphylococcus aureus), mastitis (Streptococcus uberis), parasite infections as Malaria (Plasmodium falciparum) or Toxoplasmosis (Toxoplasma gondii), and plant infections as "chestnut ink" in chestnuts or "root rot" in avocado, both diseases caused by Phytophthora cinnamomi. Both extracts verified activity against all the tested species demonstrating their potentiality to be used for the development of biocides to control a wide range of pathogenic agents; at the same time that they contribute to winemaking industry residues valorisationThis research was supported by projects GPC2017/04 (Consolidated Research Groups Program) & ED431E 2018/01 Cross-Research in Environmental Technologies (CRETUS) (Xunta de Galicia, Spain)info:eu-repo/semantics/publishedVersio

Exploring the powerful phytoarsenal of white grape marc against bacteria and parasites causing significant diseases

Natural extracts containing high polyphenolic concentration possess antibacterial, anti-parasitic and fungicidal activities. The present research characterises two extracts based on white grape marc, a winemaking by-product, describing their physicochemical features and antimicrobial capacities. The main components of these extracts are phenolic acids, flavan-3-ols and their gallates and flavonols and their glycosides. As a result of this complex composition, the extracts showed pronounced bioactivities with potential uses in agricultural, pharmaceutical and cosmetic industries. Polyphenol compounds were extracted by using hydro-organic solvent mixtures from the by-product of Albariño white wines (Galicia, NW Spain) production. The in vitro antimicrobial activity of these extracts was evaluated on Gram-positive and Gram-negative bacteria and Apicomplexan and Oomycota parasites. Microbial species investigated are causing agents of several human and animal diseases, such as foodborne illnesses (Bacillus cereus, Escherichia coli, Salmonella enterica, and Toxoplasma gondii), skin infections and/or mastitis (Staphylococcus aureus and Streptococcus uberis), malaria (Plasmodium falciparum) and plant infections as “chestnut ink” or “root rot” (Phytophthora cinnamomi). Both extracts showed activity against all the tested species, being nontoxic for the host. So, they could be used for the development of biocides to control a wide range of pathogenic agents and contribute to the enhancement of winemaking industry by-products

Ética de la investigación en ciencias sociales. El problematorio de ética, un recurso pedagógico para los dilemas de la investigación contemporánea

Depto. de Antropología Social y Psicología SocialFac. de Ciencias Políticas y SociologíaFALSEsubmitte

Pre-treatment and extraction techniques for recovery of added value compounds from wastes throughout the agri-food chain

The enormous quantity of food wastes discarded annually force to look for alternatives for this interesting feedstock. Thus, food bio-waste valorisation is one of the imperatives of the nowadays society. This review is the most comprehensive overview of currently existing technologies and processes in this field. It tackles classical and innovative physical, physico-chemical and chemical methods of food waste pre-treatment and extraction for recovery of added value compounds and detection by modern technologies and are an outcome of the COST Action EUBIS, TD1203 Food Waste Valorisation for Sustainable Chemicals, Materials and Fuels

Brain mitochondria bioenergetics, nitrergic and neurotensinergic systems

Mitochondria display a central role in cellular activity, being essential for energetic metabolism, Ca2+ homeostasis and cell signalling. The brain is one of the organs with the highest oxygen consumption of the human body, which is employed, in great proportion, to maintain and restore ionic equilibria through neuronal membranes in resting conditions and after the passage of the nervous impulse. Furthermore, neurons rely almost exclusively on ATP synthesis from the mitochondrial respiratory chain and oxidative phosphorylation to fulfill their energy requirements for neurotransmitter synthesis, release and reuptake. Differences between the characteristics of astrocyte and neuron mitochondria are evident such as for instance the distribution and organization of supercomplex respiratory chain components. In addition, some differences between oligodendrocytes and astrocytes bioenergetics have been reported.According to their distribution within the neurons, mitochondria are termed synaptic, when located within the nerve endings and non-synaptic ones, when present in neuronal soma. Environmental and energy demand differences for synaptic mitochondria versus non-synaptic mitochondria are apparent. Nitric oxide (NO) is a free radical that acts as an intercellular messenger in physiological processes such as neurotransmission, among other functions. Nitric oxide is generated by the activity of three NO synthase (NOS) enzyme isoforms. One of them, the neuronal NOS (nNOS) predominates in neuronal tissue. At central nervous system, besides the so-called classic neurotransmitters, a constellation of peptides have been identified. They present pharmacological characteristics and are colocalized and coreleased together with the classic neurotransmitters.Neurotensin is a tridecapeptide which at both central and peripheral nervous systems exerts a wide spectrum of effects. Neurotensin acts as a neuromodulator or as a neurotransmitter through its binding to specific receptors. The most important receptors are coupled to G protein, and are termed NTS1 and NTS2, which bind respectively the peptide with high and low affinity.When neurotensin binds to NTS2 receptor, it exerts either agonist or antagonist activity, according to this receptor-mediated pathway. The blockade of NTS2 receptor by levocabastine leads to a decrease in NOS activity accompanied by an enhancement of nNOS expression in brain mitochondria. At the same time, the activity of mitochondrial enzymatic complexes is markedly diminished. It is suggested an interrelationship between the neurotensinergic and the nitrergic systems. However, the effects of NTS2 activity on mitochondrial bioenergetics are likely to be independent of the regulation of NO synthesis.Fil: Rodríguez de Lores Arnaiz, Georgina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Lores Arnaiz, Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentin