RESUMO
In Mexico, there is a deficit in the production of pine resin, because it relies on natural forests only. Therefore, it is necessary to select provenances and phenotypes of potential species such as P. oocarpa. The objective was to determine the difference between provenances and the variation in resin components and quality, as well as the effect of geographic and climatic factors. Resin from five provenances was collected from southern Mexico. The percentage of rosin, turpentine and water was obtained, as well as the acidity and saponification index. P. oocarpa resin had 80.94% rosin, 7.7% turpentine and 11.49% water. The saponification and acidity index was 125.47 and 117.49 mg KOH.g-1, respectively. All variables showed differences (p ≤ 0.0001) between provenances. The provenance contributed between 6.44 and 11.71% to the total variance, the error contributed between 88.29 and 93.56%. Geographic and climatic variables only had an effect on the percentage of turpentine; the correlation was negative with altitude and longitude, but positive with temperature and precipitation. The results allow defining seed collection sites for resin plantations and orienting the selection for a P. oocarpa improvement program.
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Cerebral palsy (CP) in children constitutes a set of movement and body posture disorders caused by brain injury, which in turn is associated with a series of intestinal, respiratory, and malnutrition conditions. Twenty-four children were selected and included for the present study and subdivided into two groups: (1) children who included modern kefir (containing 12 probiotic species) in their diet; and (2) control group (not including kefir in their diet). The group supplemented with modern kefir received a beverage with multi probiotic species and the control group received commercial yogurt (which included the 2 typical lactic acid bacteria) for 7 weeks. Anthropometric variables, resting energy expenditure, presence, and diagnosis of functional digestive disorders (FDD), frequency of respiratory problems, presence of elevated C-reactive protein, differential count of leukocytes were evaluated. A significant increase in weight and height was found in the kefir group at the final time point. In addition, kefir intake promoted a significant reduction in functional constipation and stool hardness and increased the absolute value of blood lymphocytes. Since the fermented milk beverage modern kefir improves constipation, which is the most important FDD in children with CP and the nutritional and immune status, it could be considered an important strategy to improve health in these children.
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Calcium-activated chloride channels (CaCCs) play important roles in many physiological processes and their malfunction is implicated in diverse pathologies such as cancer, asthma, and hypertension. TMEM16A and TMEM16B proteins are the structural components of the CaCCs. Recent studies in cell cultures and animal models have demonstrated that pharmacological inhibition of CaCCs could be helpful in the treatment of some diseases, however, there are few specific modulators of these channels. CaCCs and Transient Receptor Potential Vanilloid-4 (TRPV4) channels are co-expressed in some tissues where they functionally interact. TRPV4 is activated by different stimuli and forms a calcium permeable channel that is activated by GSK1016790A and antagonized by GSK2193874. Here we report that GSK2193874 enhances the chloride currents mediated by TMEM16B expressed in HEK cells at nanomolar concentrations and that GSK1016790A enhances native CaCCs of Xenopus oocytes. Thus, these compounds may be used as a tool for the study of CaCCs, TRPV4 and their interactions.
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Spontaneously hypertensive rats (SHR) are widely used as model to investigate the pathophysiological mechanisms of essential hypertension. Catecholamine plasma levels are elevated in SHR, suggesting alterations of the sympathoadrenal axis. The residual hypertension in sympathectomized SHR is reduced after demedullation, suggesting a dysfunction of the adrenal medulla. Intact adrenal glands exposed to acetylcholine or high K+ release more catecholamine in SHR than in normotensive Wistar Kyoto (WKY) rats, and adrenal chromaffin cells (CCs) from SHR secrete more catecholamines than CCs from WKY rats. Since Ca2+ entry through voltage-gated Ca2+ channels (VGCC) triggers exocytosis, alterations in the functional properties of these channels might underlie the enhanced catecholamine release in SHR. This study compares the electrophysiological properties of VGCC from CCs in acute adrenal slices from WKY rats and SHR at an early stage of hypertension. No significant differences were found in the macroscopic Ca2+ currents (current density, IV curve, voltage dependence of activation and inactivation, kinetics) between CCs of SHR and WKY rats, suggesting that Ca2+ entry through VGCC is not significantly different between these strains, at least at early stages of hypertension. Ca2+ buffering, sequestration and extrusion mechanisms, as well as Ca2+ release from intracellular stores, must now be evaluated to determine if alterations in their function can explain the enhanced catecholamine secretion reported in CCs from SHR.
Assuntos
Canais de Cálcio/metabolismo , Ativação do Canal Iônico , Animais , Comunicação Autócrina/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Células Cromafins/efeitos dos fármacos , Células Cromafins/metabolismo , Ativação do Canal Iônico/efeitos dos fármacos , Masculino , Níquel/farmacologia , Nifedipino/farmacologia , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKYRESUMO
Network dynamics denoted by synchronous firing of neuronal pools rely on synaptic interactions and intrinsic properties. In striatal medium spiny neurons, N-methyl-d-aspartate (NMDA) receptor activation endows neurons with nonlinear capabilities by inducing a negative-slope conductance region (NSCR) in the current-voltage relationship. Nonlinearities underlie associative learning, procedural memory, and the sequential organization of behavior in basal ganglia nuclei. The cholinergic system modulates the function of medium spiny projection neurons through the activation of muscarinic receptors, increasing the NMDA-induced NSCR. This enhancement is reflected as a change in the NMDA-induced network dynamics, making it more synchronous. Nevertheless, little is known about the contribution of intrinsic properties that promote this activity. To investigate the mechanisms underlying the cholinergic modulation of bistable behavior in the striatum, we used whole cell and calcium-imaging techniques. A persistent sodium current modulated by muscarinic receptor activation participated in the enhancement of the NSCR and the increased network synchrony. These experiments provide evidence that persistent sodium current generates bistable behavior in striatal neurons and contributes to the regulation of synchronous network activity. The neuromodulation of bistable properties could represent a cellular and network mechanism for cholinergic actions in the striatum.
Assuntos
Corpo Estriado/fisiologia , Neurônios/fisiologia , Receptores Muscarínicos/metabolismo , Canais de Sódio/metabolismo , Potenciais de Ação , Animais , Cálcio/metabolismo , Corpo Estriado/citologia , Técnicas In Vitro , Potenciais da Membrana , N-Metilaspartato/metabolismo , Técnicas de Patch-Clamp , Ratos , Ratos Wistar , Receptores de N-Metil-D-Aspartato/metabolismo , Sódio/metabolismoRESUMO
The effects of D1/5 dopamine agonists on spontaneous excitatory postsynaptic currents (sEPSCs) were studied in neurons of the rat globus pallidus using whole-cell recordings in the presence of TTX and bicuculline. In this condition, CNQX abolished the sEPSCs, indicating that they were solely mediated by AMPA receptors. SKF 38393, a D1-like agonist, increased the frequency but not the amplitude of the sEPSCs, suggesting a presynaptic site of action. The increase in frequency was blocked by SCH 23390, a D1/5 antagonist. Quinpirole, a D2-like agonist, decreased the frequency but did not affect the amplitude of the synaptic currents. SKF 38393 increased the frequency of sEPSCs currents, even in presence of quinpirole, indicating that D1/5- and D2-like receptors independently modulate glutamate release upon a single neuron. The results suggest that the dopaminergic control of the glutamate transmission in the globus pallidus may play a role in processing cortical information in the indirect pathway of the basal ganglia.
Assuntos
Dopamina/metabolismo , Globo Pálido/metabolismo , Ácido Glutâmico/metabolismo , Terminações Pré-Sinápticas/metabolismo , Receptores de Dopamina D1/metabolismo , Transmissão Sináptica/fisiologia , Animais , Agonistas de Dopamina/farmacologia , Antagonistas de Dopamina/farmacologia , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/fisiologia , Antagonistas GABAérgicos/farmacologia , Globo Pálido/efeitos dos fármacos , Masculino , Vias Neurais/efeitos dos fármacos , Vias Neurais/metabolismo , Técnicas de Cultura de Órgãos , Técnicas de Patch-Clamp , Terminações Pré-Sinápticas/efeitos dos fármacos , Ratos , Ratos Wistar , Receptores de AMPA/efeitos dos fármacos , Receptores de AMPA/metabolismo , Receptores de Dopamina D1/efeitos dos fármacos , Receptores de Dopamina D2/efeitos dos fármacos , Receptores de Dopamina D2/metabolismo , Bloqueadores dos Canais de Sódio/farmacologia , Transmissão Sináptica/efeitos dos fármacosRESUMO
Dopamine is a critical modulator of striatal function; its absence produces Parkinson's disease. Most cellular actions of dopamine are still unknown. This work describes the presynaptic actions of dopaminergic receptor agonists on GABAergic transmission between neostriatal projection neurons. Axon collaterals interconnect projection neurons, the main axons of which project to other basal ganglia nuclei. Most if not all of these projecting axons pass through the globus pallidus. Thus, we lesioned the intrinsic neurons of the globus pallidus and stimulated neostriatal efferent axons antidromically with a bipolar electrode located in this nucleus. This maneuver revealed a bicuculline-sensitive synaptic current while recording in spiny cells. D1 receptor agonists facilitated whereas D2 receptor agonists depressed this synaptic current. In contrast, a bicuculline-sensitive synaptic current evoked by field stimulation inside the neostriatum was not consistently modulated, in agreement with previous studies. The data are discussed in light of the most recent experimental and modeling results. The conclusion was that inhibition of spiny cells by axon collaterals of other spiny cells is quantitatively important; however, to be functionally important, this inhibition might be conditioned to the synchronized firing of spiny neurons. Finally, dopamine exerts a potentially important role regulating the extent of lateral inhibition.