RESUMO
This work aimed to study different seeding rates in soybean, at management zones determined by the mapping of the soil apparent electrical conductivity (ECa) and its relationships with plant phenology and grain yield (GY). The experiment consisted of a completely randomized design, with six replications. The plant population ranged between 311,000, 360,000, and 422,000 plants ha-1, and the fixed population (360,000 plants ha-1). The management zone with the least yield potential, received the highest seed population. The management zone with the highest plant vigor potential, received the lowest seed population. The variables plant height, Normalized Difference Vegetation Index (NDVI) at 50, 66, and 92 days after emergence (DAE), one hundred-grain weight, and GY were analyzed. ECa maps can be used to decide the seed population of the soybean. The decision strategy of increasing 20% of the seed soybean population on the smaller ECa map zones, and decreasing 20% seed population on higher ECa zones was effective and resulted in similar GY, even with the negative pressure of the high resistance of penetration (RP) values in some zones. GY map variability was influenced by ECa 0-0.2 m, by NDVI at 92 DAE and by RP 0.4-0.6 m soil layer.
Assuntos
Glycine max , Condutividade Elétrica , Sementes , SoloRESUMO
Currently available antidepressants have a substantial time lag to induce therapeutic response and a relatively low efficacy. The development of drugs that addresses these limitations is critical to improving public health. Cannabidiol (CBD), a non-psychotomimetic component of Cannabis sativa, is a promising compound since it shows large-spectrum therapeutic potential in preclinical models and humans. However, its antidepressant properties have not been completely investigated. Therefore, the aims of this study were to investigate in male rodents (i) whether CBD could induce rapid and sustained antidepressant-like effects after a single administration and (ii) whether such effects could be related to changes in synaptic proteins/function. Results showed that a single dose of CBD dose-dependently induced antidepressant-like effect (7-30 mg/kg) in Swiss mice submitted to the forced swim test (FST), 30 min (acute) or 7 days (sustained) following treatment. Similar effects were observed in the Flinders Sensitive and Flinders Resistant Line (FSL/FRL) rats and the learned helplessness (LH) paradigm using Wistar rats. The acute antidepressant effects (30 min) were associated with increased expression of synaptophysin and PSD95 in the medial prefrontal cortex (mPFC) and elevated BDNF levels in both mPFC and hippocampus (HPC). CBD also increased spine density in the mPFC after 30 min, but not 7 days later. Intracerebroventricular injection of the TrkB antagonist, K252a (0.05 nmol/µL), or the mTOR inhibitor, rapamycin (1 nmol/µL), abolished the behavioral effects of CBD. These results indicate that CBD induces fast and sustained antidepressant-like effect in distinct animal models relevant for depression. These effects may be related to rapid changes in synaptic plasticity in the mPFC through activation of the BDNF-TrkB signaling pathway. The data support a promising therapeutic profile for CBD as a new fast-acting antidepressant drug.
Assuntos
Antidepressivos/farmacologia , Fator Neurotrófico Derivado do Encéfalo/efeitos dos fármacos , Canabidiol/farmacologia , Córtex Pré-Frontal/efeitos dos fármacos , Animais , Comportamento Animal/efeitos dos fármacos , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Depressão/tratamento farmacológico , Hipocampo/metabolismo , Masculino , Camundongos , Córtex Pré-Frontal/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
Activation of purinergic receptors by ATP (P2R) modulates glutamate release and the activation of post-synaptic P2R is speculated to induce nitric oxide (NO) synthesis. Increased glutamatergic and nitrergic signaling have been involved in the neurobiology of stress-related psychiatric disorders such as anxiety and depression. Therefore, the aim of this study was to test the effects of two P2R antagonists (PPADS and iso-PPADS) in animals submitted to models predictive of antidepressant-, anxiolytic- and anticompulsive-like effects. Swiss mice receiving PPADS at 12.5mg/kg showed reduced immobility time in the forced swimming test (FST) similarly to the prototype antidepressant imipramine (30mg/kg). This dose was also able to decrease the number of buried marbles in the marble-burying test (MBT), an anticompulsive-like effect. However, no effect was observed in animals submitted to the elevated plus maze (EPM) and to the open field test. The systemic administration of iso-PPADS, a preferential P2XR antagonist, also reduced the immobility time in FST, which was associated to a decrease in NOx levels in the prefrontal cortex. In addition, P2X7 receptor was found co-immunoprecipitated with neuronal nitric oxide synthase (NOS1) in the prefrontal cortex. These results suggest that P2X7, possibly coupled to NOS1, could modulate behavioral responses associated to stress-related disorders and it could be a new target for the development of more effective treatments for affective disorders.
Assuntos
Antidepressivos/uso terapêutico , Comportamento Compulsivo/tratamento farmacológico , Depressão/tratamento farmacológico , Óxido Nítrico/metabolismo , Antagonistas Purinérgicos/uso terapêutico , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Comportamento Exploratório/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Resposta de Imobilidade Tônica/efeitos dos fármacos , Resposta de Imobilidade Tônica/fisiologia , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Óxido Nítrico Sintase Tipo II/metabolismo , Paroxetina/farmacologia , Paroxetina/uso terapêutico , Antagonistas Purinérgicos/farmacologia , Fosfato de Piridoxal/análogos & derivados , Fosfato de Piridoxal/farmacologia , Fosfato de Piridoxal/uso terapêutico , Ratos , Receptores Purinérgicos/metabolismo , Natação/psicologiaRESUMO
AIM OF THE STUDY: Ilex paraguariensis St. Hilaire (Aquifoliaceae) is a plant widely cultivated in South America that is used to prepare a tea-like beverage with a reputation to improve cognitive function, a response that has been attributed to the constituents of the leaves, especially caffeine. Our previous study indicated that the hydroalcoholic extract of Ilex paraguariensis presents an antiparkinsonian profile in reserpine- and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP)-treated rodents. MATERIALS AND METHODS: In the present study, the effects of the hydroalcoholic extract of Ilex paraguariensis on the short- and long-term learning and memory of rats were assessed with the social recognition, Morris water maze, and step-down inhibitory avoidance tasks. RESULTS: A preliminary HPLC fingerprint of the plant extract confirmed the presence of caffeine (the major compound), rutin and kaemperol, and revealed the absence of detectable concentrations of caffeic acid, quercetin and ursolic acid. Acute pre-training intraperitoneal (i.p.) or oral administration of the extract of Ilex paraguariensis improved the short-term social memory in a specific manner as well as facilitated the step-down inhibitory avoidance short-term memory evaluated 1.5h after training. Moreover, a synergistic response was observed following the co-administration of 'non-effective' doses of caffeine and Ilex paraguariensis in the social memory. In contrast, pre-training administration of hydroalcoholic extract of Ilex paraguariensis did not alter the step-down inhibitory avoidance long-term memory evaluated 24h after training, while the highest dose tested (250 mg/kg, i.p.) disrupted the animals' performance in a cued version of the Morris water maze. CONCLUSION: These results partly substantiate the traditional use of mate tea for improvement of cognition indicating that acute administration of hydroalcoholic extract of Ilex paraguariensis differentially modulates short- and long-term learning and memory in rats probably through its antagonist's action on adenosine receptors.