Basolateral amygdala circuitry in positive and negative valence

Publication date: April 2018
Source:Current Opinion in Neurobiology, Volume 49
Author(s): Pia-Kelsey O'Neill, Felicity Gore, C Daniel Salzman
All organisms must solve the same fundamental problem: they must acquire rewards and avoid danger in order to survive. A key challenge for the nervous system is therefore to connect motivationally salient sensory stimuli to neural circuits that engage appropriate valence-specific behavioral responses. Anatomical, behavioral, and electrophysiological data have long suggested that the amygdala plays a central role in this process. Here we review experimental efforts leveraging recent technological advances to provide previously unattainable insights into the functional, anatomical, and genetic identity of neural populations within the amygdala that connect sensory stimuli to valence-specific behavioral responses.



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Current and emerging neuromodulation therapies for addiction: insight from pre-clinical studies

Publication date: April 2018
Source:Current Opinion in Neurobiology, Volume 49
Author(s): Meaghan Creed
Neuromodulation therapies such as deep brain stimulation or transcranial magnetic stimulation have shown promise in reducing symptoms of addiction when applied to the prefontal cortex, nucleus accumbens or subthalamic nucleus. Pre-clinical investigations implicate modulation of the cortico-basal ganglia network in these therapeutic effects, and this mechanistic understanding is necessary to optimize stimulation paradigms. Recently, the principle that neuromodulation can reverse drug-evoked synaptic plasticity and reduce behavioral symptoms of addiction has inspired novel stimulation paradigms that have long-term effects in animal models. Pre-clinical studies have also raised the possibility that tailoring neuromodulation protocols can modulate distinct symptoms of addiction. Combining mechanistic knowledge of circuit dysfunction with emerging technologies for non-invasive neuromodulation holds promise for developing therapies for addiction and related disorders.



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Editorial overview: Neurobiology of behavior

Publication date: Available online 8 March 2018
Source:Current Opinion in Neurobiology
Author(s): Kay M Tye, Naoshige Uchida




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Bleaching of biofilm-forming algae induced by UV-C treatment: a preliminary study on chlorophyll degradation and its optimization for an application on cultural heritage

Abstract

Green microalgae colonizing stone surfaces represent a major problem for the conservation of heritage monuments, since they lead to biodegradation and aesthetic issues. Previous studies in La Glacière show cave (France) have demonstrated that UV-C may have a strong effect on microalgae, thus leading to chlorophyll bleaching, which was increased when biofilms were maintained under VIS-light condition unlike to those maintained in the dark. To understand the physiological mechanisms underlying this response and in order to optimize in situ treatment, 30 kJ m⁻² UV-C exposure times were applied to Chlorophyta Chlorella sp. and chlorophyll degradation kinetics were then monitored. UV-C irradiation was enough to inhibit photosynthesis and to directly kill all algal cells. Results also showed that chlorophyll a was degraded faster than chlorophyll b and that 14 h were necessary for complete degradation of all the present chlorophyll. In addition, our results highlighted the importance of visible light exposition after UV-C treatment which leading to chlorophyll bleaching. Irradiated algae cultivated in the dark were still green 5 days after treatment while cultivated samples in the light lost their green color after 14 h. An efficient UV-C treatment applicable to show caves and other heritage monuments was proposed.

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Levels of urinary metabolites of four PAHs and cotinine determined in 1016 volunteers living in Central Italy

Abstract

Polycyclic aromatic hydrocarbons (PAH) are products of the incomplete combustion of organic materials, and exposure of the general population to PAH is ubiquitous. They are also present in tobacco smoke. Some PAH are classified as carcinogens. Urine samples from 747 non-smoking and 269 smoking subjects living in the same area of Central Italy were analyzed in order to determine reference values for PAHs exposure of a general population. The concentration of cotinine, urinary metabolite of nicotine was also measured in these samples in order to classify the subjects as smokers or not. The median concentration and 50th percentile in females was higher than in males for all metabolites; 1- and 2-hydroxynaphtalene (1-OHNAP and 2-OHNAP) and 1-hydroxypyrene (1-OHPy), are significantly higher in smokers; on the other side 3-hydroxybenzo[a]pyrene (3-OHBaPy) and 6-hydroxynitropyrene (6-OHNPy) do not correlate with the cotinine concentration.

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NO 3 − /NH 4 + ratios affect nutritional homeostasis and production of Tanzania guinea grass under Cu toxicity

Abstract

Nitrogen (N) can alleviate metal toxicity. However, as of yet, there have been no studies showing the efficacy of NO₃⁻/NH₄⁺ in mitigating Cu toxicity. The objective of this study was to evaluate the Cu toxicity on the nutritional and productive attributes of Panicum maximum cv. Tanzania as well as the role of NO₃⁻ and NH₄⁺ ratios in nutritional homeostasis. The experiment was conducted using 3 × 4 factorial treatments arranged in a randomized complete block design with three replicates. The treatments were three NO₃⁻/NH₄⁺ ratios (100/0, 70/30, and 50/50) and four Cu rates (0.3, 250, 500, and 1000 μmol L⁻¹) in nutrient solution. Copper concentrations in the diagnostic leaves (DL) were highest in plants grown under 70/30 NO₃⁻/NH₄⁺ ratios and a Cu rate of 1000 μmol L⁻¹. In this combination, it was observed that DL had higher concentrations of NH₄⁺, greater glutamine synthetase activity, lower chlorophyll concentration (SPAD value), and lower shoot dry mass, suggesting high disorders of nutritional homeostasis. Plants receiving N in the form of NO₃⁻ and 1000 Cu μmol L⁻¹ showed that DL had lower concentrations of Cu, higher concentration of chlorophyll, higher NO₃⁻ concentration, higher nitrate reductase activity, and higher NO₃⁻ accumulation in the roots, suggesting a reduction in disorders of nutritional homeostasis. The disorders on mineral uptake, N assimilation, and biomass production caused by Cu toxicity are shown to be affected by NO₃⁻/NH₄⁺ ratios, and N supply via NO₃⁻ allowed for better homeostasis of the forage grass.

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Detoxification, oxidative stress, and cytogenotoxicity of crack cocaine in the brown mussel Perna perna

Abstract

The presence of cocaine and its metabolites and by-products has been identified in different aquatic matrices, making crack cocaine the target of recent studies. The aim of this study was to evaluate the sublethal effects of crack on the brown mussel Perna perna. Mussels were exposed to three concentrations of crack cocaine (0.5, 5.0, and 50.0 μg L⁻¹) for 168 h. Gills, digestive glands, and hemolymph were extracted and analyzed after three different exposure times using a suite of biomarkers (EROD, DBF, GST, GPX, LPO, DNA damage, ChE, and lysosomal membrane stability [LMS]). After 48 and 96 h of exposure, EROD, DBF, GST, GPX activities and DNA strand breaks in the gills increased significantly after 48 and 96 h of exposure. Alterations in LMS were also observed in the mussels exposed to all crack concentrations after 96 and 168 h. Our results demonstrated that crack cocaine is metabolized by CYP-like and GST activities in the gills. GPX was not able to prevent primary genetic damage, and cytotoxic effects in the hemocytes were also observed in a dose- and time-dependent response. Our study shows that the introduction of illicit drugs into coastal ecosystems must be considered a threat to marine organisms.

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