Daily pattern of pituitary glutamine, glutamate, and aspartate content disrupted by cadmium exposure

Data on the Quantification of Aspartate, GABA and Glutamine Levels in the Spinal Cord of Larval Sea Lampreys after a Complete Spinal Cord Injury

We used high-performance liquid chromatography (HPLC) methods to quantify aspartate, GABA, and glutamine levels in the spinal cord of larval sea lampreys following a complete spinal cord injury. Mature larval sea lampreys recover spontaneously from a complete spinal cord transection and the changes in neurotransmitter systems after spinal cord injury might be related to their amazing regenerative capabilities. The data presented here show the concentration of the aminoacidergic neurotransmitters GABA (and its precursor glutamine) and aspartate in the spinal cord of control (non-injured) and 2-, 4-, and 10-week post-lesion animals. Statistical analyses showed that GABA and aspartate levels significantly increase in the spinal cord four weeks after a complete spinal cord injury and that glutamine levels decrease 10 weeks after injury as compared to controls. These data might be of interest to those studying the role of neurotransmitters and neuromodulators in recovery from spinal cord injury in vertebrates.

Cross-species physiological interactions of endocrine disrupting chemicals with the circadian clock

Endocrine disrupting chemicals (EDCs) are endocrine-active chemical pollutants that disrupt reproductive, neuroendocrine, cardiovascular and metabolic health across species. The circadian clock is a transcriptional oscillator responsible for entraining 24-hour rhythms of physiology, behavior and metabolism. Extensive bidirectional cross talk exists between circadian and endocrine systems and circadian rhythmicity is present at all levels of endocrine control, from synthesis and release of hormones, to sensitivity of target tissues to hormone action. In mammals, a range of hormones directly alter clock gene expression and circadian physiology via nuclear receptor (NR) binding and subsequent genomic action, modulating physiological processes such as nutrient and energy metabolism, stress response, reproductive physiology and circadian behavioral rhythms. The potential for EDCs to perturb circadian clocks or circadian-driven physiology is not well characterized. For this reason, we explore evidence for parallel endocrine and circadian disruption following EDC exposure across species. In the reviewed studies, EDCs dysregulated core clock and circadian rhythm network gene expression in brain and peripheral organs, and altered circadian reproductive, behavioral and metabolic rhythms. Circadian impacts occurred in parallel to endocrine and metabolic alterations such as impaired fertility and dysregulated metabolic and energetic homeostasis. Further research is warranted to understand the nature of interaction between circadian and endocrine systems in mediating physiological effects of EDC exposure at environmental levels.

Effect of both selenium and biosynthesized nanoselenium particles on cadmium-induced neurotoxicity in albino rats

Because cadmium (Cd) is not naturally degradable by ecosystems, it interferes with many types of food chains. Cd accumulates in the kidney, liver and in the nervous tissues, especially the brain. The neurotoxicity of Cd is very high, as it alters the integrity, and increases the permeability, of the blood–brain barrier. Cd penetrates and accumulates in neurons in the brains of rats. This study reveals that Cd decreases antioxidant enzymes and increases oxidative stress in the brain. In addition, Cd increases lipid peroxidation of brain tissues. Cd increases the expression of the Cu/Zn superoxide dismutase gene. It also affects cholinergic, glutamatergic, gamma-Aminobutyric acid (GABAergic), dopamine, serotonin and acetylcholine neurotransmitters in brain tissue. Consequently, Cd increases the formation of amyloid β, a neurotoxic index, and induces apoptosis by changing the quality and the quantity of Bcl-2, Bax and p53 proteins. In conclusion, both selenium and nanoselenium show potential antioxidant activity and promote recovery from the neurotoxic action of Cd.

Joint effects of chronic exposure to environmentally relevant levels of nonylphenol and cadmium on the reproductive functions in male rockfish Sebastiscus marmoratus

Nonylphenol (NP) and Cadmium (Cd) are two common contaminants that can be detected in aquatic environments. Nevertheless, the combined toxicity of NP and Cd at environmentally relevant concentrations in aquatic organisms has not been thoroughly characterized to date. In the present study, the interactions between NP and Cd on male Sebastiscus marmoratus were studied. After 21 days of exposure, the brain aromatase activity was observed to be significantly induced by 100 ng/L NP and 40 μg/L Cd, whereas all of the concentrations of co-treatment resulted in an increase in brain aromatase activity. Additionally, NP could also reduce plasma testosterone concentration, while NP, Cd and their mixture could induce plasma 17β-estradiol (E2) concentration and VTG concentration. The interactions between NP and Cd on the reproductive physiology were antagonism. Our results also support the notion of using these indicators as biomarkers for exposure to EDCs and further extend the boundary of biomonitoring to environmental levels.

Cadmium chronotoxicity at pituitary level: effects on plasma ACTH, GH, and TSH daily pattern

Cadmium is an endocrine disruptor that has been shown to induce chronotoxic effects. The present study was designed to evaluate the possible cadmium effects on the daily secretory pattern of adrenocorticotropin hormone (ACTH), growth hormone (GH), and thyroid-stimulating hormone (TSH) in adult male Sprague-Dawley rats. For this purpose, animals were treated with cadmium at two different doses [25 and 50 mg/l cadmium chloride (CdCl(2))] in the drinking water for 30 days. Control age-matched rats received cadmium-free water. After the treatment, rats were killed at six different time intervals throughout a 24-h cycle. Cadmium exposure modified the 24-h pattern of plasma ACTH and GH levels, as the peak of ACTH content between 12:00 and 16:00 h in controls appeared at 12:00 h in the group treated with the lowest dose used, while it appeared between 16:00 and 20:00 h in rats exposed to 50 mg/l CdCl(2). In addition, the peak of GH content found at 04:00 h in controls moved to 16:00 h in rats exposed to 25 mg/l CdCl(2), and the highest dose used abolished 24-h changes of GH secretion. The metal treatment did not modify ACTH secretory pattern. Exposure to cadmium also increased ACTH and TSH medium levels around the clock with both doses used. These results suggest that cadmium modifies ACTH and TSH medium levels around the clock, as well as disrupted ACTH and GH secretory pattern, thus confirming the metal chronotoxicity at pituitary level.

Cadmium effects on 24h changes in glutamate, aspartate, glutamine, GABA and taurine content of rat striatum

This work evaluates the possible changes in 24 h variations of striatal aspartate, glutamate, glutamine, gamma-aminobutyric acid (GABA) and taurine content after oral cadmium treatment. Male rats were submitted to cadmium exposure at two doses (25 and 50 mg/L of cadmium chloride (CdCl(2))) in the drinking water for 30 days. Control rats received cadmium-free water. After the treatment, rats were killed at six different time intervals throughout a 24 h cycle. Differential effects of cadmium on 24 h amino acid fluctuations were observed. Metal exposure modified the daily pattern of the amino acids concentration found in control animals, except for GABA and taurine with the lowest dose used. Exposure to 25 mg/L of CdCl(2) decreased mean content of aspartate, as well as GABA concentration. These results suggest that cadmium exposure affects 24 h changes of the studied amino acids concentration in the striatum, and those changes may be related to alterations in striatal function.