Neodymium as an alternative contrast for uranium in electron microscopy.

Uranyl acetate is the standard contrasting agent in electron microscopy (EM), but it is toxic and radioactive. We reasoned neodymium acetate might substitute uranyl acetate as a contrasting agent, and we find that neodymium acetate indeed can replace uranyl acetate in several routine applications. Since neodymium acetate is not toxic, not radioactive and easy to use, we foresee neodymium will replace uranyl in many EM sample preparation applications worldwide.

A Fluorescent ESIPT Probe for Imaging CO-Releasing Molecule-3 in Living Systems.

CO-releasing molecule-3 (CORM-3) has been widely used recently as a convenient and safe CO donor to release exogenous CO in living cells and to study the effects of CO on cellular systems. Accordingly, development of effective methods for detecting and tracking CORM-3 in living systems is of great significance. In this work, a readily available fluorescent probe for detection of CORM-3 was reported for the first time. This probe is based on an excited-state intramolecular proton transfer (ESIPT) dye phthalimide and uses the reducing ability of CORM-3 to convert a nitro group to an amino group, and more importantly, it can be used for rapid, highly selective, and sensitive detection of CORM-3 with a distinct turn-on green fluorescence change in aqueous solution, living cells, and animals, thus providing a useful tool for studying CORM-3 in living systems.

Chimeric mouse model for MRI contrast agent evaluation.

PURPOSE: While rodents are the primary animal models for contrast agent evaluation, rodents can potentially misrepresent human organ clearance of newly developed contrast agents. For example, gadolinium (Gd)-BOPTA has ~50% hepatic clearance in rodents, but ~5% in humans. This study demonstrates the benefit of chimeric mice expressing human hepatic OATPs (organic anion-transporting polypeptides) to improve evaluation of novel contrast agents for clinical use. METHODS: FVB (wild-type) and OATP1B1/1B3 knock-in mice were injected with hepatospecific MRI contrast agents (Gd-EOB-DTPA, Gd-BOPTA) and nonspecific Gd-DTPA. T1 -weighted dynamic contrast-enhanced MRI was performed on mice injected intravenously. Hepatic MRI signal enhancement was calculated per time point. Mass of gadolinium cleared per time point and percentage elimination by means of feces and urine were also measured. RESULTS: Following intravenous injection of Gd-BOPTA in chimeric OATP1B1/1B3 knock-in mice, hepatic MRI signal enhancement and elimination by liver was more reflective of human hepatic clearance than that measured in wild-type mice. Gd-BOPTA hepatic MRI signal enhancement was reduced to 22% relative to wild-type mice. Gd-BOPTA elimination in wild-type mice was 83% fecal compared with 32% fecal in chimeric mice. Hepatic MRI signal enhancement and elimination for Gd-EOB-DTPA and Gd-DTPA were similar between wild-type and chimeric cohorts. CONCLUSION: Hepatic MRI signal enhancement and elimination of Gd-EOB-DTPA, Gd-BOPTA, and Gd-DTPA in chimeric OATP1B1/1B3 knock-in mice closely mimics that seen in humans. This study provides evidence that the chimeric knock-in mouse is a more useful screening tool for novel MRI contrast agents destined for clinical use as compared to the traditionally used wild-type models.

Selective binding of an organoruthenium complex to G-rich human telomeric sequence by tandem mass spectrometry.

RATIONALE: Human telomeric DNA is reported to be a potential target for anticancer organometallic ruthenium(II) complexes, however, the interaction sites were not clearly discriminated and identified. METHODS: In the current study, tandem mass spectrometry (MS/MS) using collision-induced dissociation (CID) was firstly introduced to identify the interaction sites of an organometallic ruthenium(II) complex [(η6 -biphenyl)Ru(en)Cl][PF6 ] (1; en = ethylenediamine) with 5'-T1 T2 A3 G4 G5 G6 -3' (I), the repeating unit of human telomeric DNA, in both positive- and negative-ion mode at a low reaction molar ratio (1/I = 0.2) which was applied to preserve the site selectivity. RESULTS: Mass spectrometric results showed that mono-ruthenated I was the main product under the conditions. In positive-ion mode, MS/MS results indicated that ruthenium complex 1 binds to T2 or G6 in strand I. However, in negative-ion mode, no efficient information was obtained for exact identification of ruthenation sites which may be attributed to losses of fragment ions due to charge neutralization by the coordination of the positively charged ruthenium complex to the short MS/MS fragments. CONCLUSIONS: This is the first report of using top-down MS to characterize the interactions of organometallic ruthenium(II) complexes and human telomeric DNA. Thymine can be thermodynamically competitive with guanine for binding to ruthenium complexes even at low reaction molar ratio, which inspired us to explore in greater depth the significance of thymine binding.

Half-Sandwich Iridium and Ruthenium Complexes: Effective Tracking in Cells and Anticancer Studies.

Half-sandwich metal-based anticancer complexes suffer from uncertain targets and mechanisms of action. Herein we report the observation of the images of half-sandwich iridium and ruthenium complexes in cells detected by confocal microscopy. The confocal microscopy images showed that the cyclopentadienyl iridium complex 1 mainly accumulated in nuclei in A549 lung cancer cells, whereas the arene ruthenium complex 3 is located in mitochondria and lysosomes, mostly in mitochondria, although both complexes entered A549 cells mainly through energy-dependent active transport. The nuclear morphological changes caused by Ir complex 1 were also detected by confocal microscopy. Ir complex 1 is more potent than cisplatin toward A549 and HeLa cells. DNA binding studies involved interaction with the nucleobases 9-ethylguanine, 9-methyladenine, ctDNA, and plasmid DNA. The determination of bovine serum albumin binding was also performed. Hydrolysis, stability, nucleobase binding, and catalytic NAD+/NADH hydride transfer tests for complexes 1 and 3 were also carried out. Both complexes activated depolarization of mitochondrial membrane potential and intracellular ROS overproduction and induced cell apoptosis. Complex 3 arrested the cell cycle at the G0/G1 phase by inactivation of CDK 4/cyclin D1. This work paves the way to track and monitor half-sandwich metal complexes in cells, shines a light on understanding their mechanism of action, and indicates their potential application as theranostic agents.

Review: ecotoxicity of organic and organo-metallic antifouling co-biocides and implications for environmental hazard and risk assessments in aquatic ecosystems.

Hazard assessments of Irgarol 1051, diuron, 2-(thiocyanomethylthio)benzothiazole (TCMTB), dichloro-octylisothiazolin (DCOIT), chlorothalonil, dichlofluanid, thiram, zinc pyrithione, copper pyrithione, triphenylborane pyridine (TPBP), capsaicin, nonivamide, tralopyril and medetomidine were performed to establish robust environmental quality standards (EQS), based on predicted no effect concentrations (PNECs). Microalgae, zooplankton, fish and amphibians were the most sensitive ecological groups to all the antifoulants evaluated, especially in the early life stages. No differences were identified between freshwater and seawater species. The use of toxicity tests with non-standard species is encouraged because they increase the datasets, allowing EQS to be derived from probabilistic-based PNECs whilst reducing uncertainties. The global ban of tributyltin (TBT) has been heralded as a major environmental success; however, substitute antifoulants may also pose risks to aquatic ecosystems. Environmental risk assessments (ERAs) have driven decision-makings for regulating antifouling products, but in many countries there is still a lack of regulation of antifouling biocides which should be addressed.

The influence of seawater properties on toxicity of copper pyrithione and its degradation product to brine shrimp Artemia salina.

Copper pyrithione (CuPT) is a biocide, used worldwide to prevent biofouling on submerged surfaces. In aquatic environments it rapidly degrades, however, one of the degradation products (HPT) is known to react with cupric ion back to its parent compound. Not much is known about the behavior and toxicity of CuPT and its degradation product HPT in different water systems. Hence, our aim was to investigate the ecotoxicity of CuPT, HPT as well as Cu2+ to the brine shrimp Artemia salina in natural seawater and organic matter-free artificial seawater. Moreover, in order to elucidate the influence of ionic strength of water on CuPT toxicity, tests were performed in water media with modified salinity. The results showed that CuPT was the most toxic to the exposed crustaceans in a seawater media with the highest salinity and with no organic matter content. HPT in a presence of cupric ion converted to CuPT, but the measured CuPT concentrations and the mortality of A. salina in natural water were lower than in artificial water. The toxicity of CuPT to A. salina was significantly influenced by the organic matter content, salinity, and proportions of constituent salts in water. In a combination with cupric ion, non-hazardous degradation product HPT exhibits increased toxicity due to its rapid transformation to its parent compound.

Bioavailability and chronic toxicity of bismuth citrate to earthworm Eisenia andrei exposed to natural sandy soil.

The present study describes bioavailability and chronic effects of bismuth to earthworms Eisenia andrei using OECD reproduction test. Adult earthworms were exposed to natural sandy soil contaminated artificially by bismuth citrate. Average total concentrations of bismuth in soil recovered by HNO3 digestion ranged from 75 to 289mg/kg. Results indicate that bismuth decreased significantly all reproduction parameters of Eisenia andrei at concentrations ≥ 116mg/kg. However, number of hatched cocoons and number of juveniles seem to be more sensitive than total number of cocoons, as determined by IC50; i.e., 182, 123 and > 289mg/kg, respectively. Bismuth did not affect Eisenia andrei growth and survival, and had little effect on phagocytic efficiency of coelomocytes. The low immunotoxicity effect might be explained by the involvement of other mechanisms i.e. bismuth sequestered by metal-binding compounds. After 28 days of exposure bismuth concentrations in earthworms tissue increased with increasing bismuth concentrations in soil reaching a stationary state of 21.37mg/kg dry tissue for 243mg Bi/kg dry soil total content. Data indicate also that after 56 days of incubation the average fractions of bismuth available extracted by KNO3 aqueous solution in soil without earthworms varied from 0.0051 to 0.0229mg/kg, while in soil with earthworms bismuth concentration ranged between 0.310-1.347mg/kg dry soil. We presume that mucus and chelating agents produced by earthworms and by soil or/and earthworm gut microorganisms could explain this enhancement, as well as the role of dermal and ingestion routes of earthworms uptake to soil contaminant.

Synthesis and evaluation of a radiolabeled bis-zinc(II)-cyclen complex as a potential probe for in vivo imaging of cell death.

The exposition of phosphatidylserine (PS) from the cell membrane is associated with most cell death programs (apoptosis, necrosis, autophagy, mitotic catastrophe, etc.), which makes PS an attractive target for overall cell death imaging. To this end, zinc(II) macrocycle coordination complexes with cyclic polyamine units as low-molecular-weight annexin mimics have a selective affinity for biomembrane surfaces enriched with PS, and are therefore useful for detection of cell death. In the present study, a 11C-labeled zinc(II)-bis(cyclen) complex (11C-CyclenZn2) was prepared and evaluated as a new positron emission tomography (PET) probe for cell death imaging. 11C-CyclenZn2 was synthesized by methylation of its precursor, 4-methoxy-2,5-di-[10-methyl-1,4,7,10-tetraazacyclododecane-1,4,7-tricarboxylic acid tri-tert-butyl ester] phenol (Boc-Cyclen2) with 11C-methyl triflate as a prosthetic group in acetone, deprotection by hydrolysis in aqueous HCl solution, and chelation with zinc nitrate. The cell death imaging capability of 11C-CyclenZn2 was evaluated using in vitro cell uptake assays with camptothecin-treated PC-3 cells, biodistribution studies, and in vivo PET imaging in Kunming mice bearing S-180 fibrosarcoma. Starting from 11C-methyl triflate, the total preparation time for 11C-CyclenZn2 was ~40 min, with an uncorrected radiochemical yield of 12 ± 3% (based on 11C-CH3OTf, n = 10), a radiochemical purity of greater than 95%, and the specific activity of 0.75-1.01 GBq/µmol. The cell death binding specificity of 11C-CyclenZn2 was demonstrated by significantly different uptake rates in camptothecin-treated and control PC-3 cells in vitro. Inhibition experiments for 18F-radiofluorinated Annexin V binding to apoptotic/necrotic cells illustrated the necessity of zinc ions for zinc(II)-bis(cyclen) complexation in binding cell death, and zinc(II)-bis(cyclen) complexe and Annexin V had not identical binding pattern with apoptosis/necrosis cells. Biodistribution studies of 11C-CyclenZn2 revealed a fast clearance from blood, low uptake rates in brain and muscle tissue, and high uptake rates in liver and kidney, which provide the main metabolic route. PET imaging using 11C-CyclenZn2 revealed that cyclophosphamide-treated mice (CP-treated group) exhibited a significant increase of uptake rate in the tumor at 60 min postinjection, compared with control mice (Control group). The results indicate that the ability of 11C-CyclenZn2 to detect cell death is comparable to Annexin V, and it has potential as a PET tracer for noninvasive evaluation and monitoring of anti-tumor chemotherapy.

A two-photon ratiometric ESIPT probe for fast detection and bioimaging of palladium species.

A novel ratiometric ESIPT fluorescent probe, which is specific for palladium species of all the typical oxidation states (0, +2, and +4), has been designed. Notably, based on the excited state intramolecular proton transfer (ESIPT) process, the probe exhibits a ratiometric fluorescent response to palladium species with a low detection limit (9.0 nM, 0.96 ppb) in about 1.5 min at room temperature. Moreover, it has been successfully used as a two-photon ratiometric fluorescent palladium probe for in vivo and three-dimensional imaging with low cytotoxicity and autofluorescence. Compared with other reported palladium probes, the probe displays a shorter ratiometric response time and lower detection limit in milder test conditions. All of the results indicate that the probe may be favorable for environmental and biological applications.

Synthesis and evaluation of a 68Ga-labeled bradykinin B1 receptor agonist for imaging with positron emission tomography.

A novel 68Ga-labeled bradykinin B1 receptor (B1R) agonist, 68Ga-Z01115, was synthesized and evaluated for imaging with positron emission tomography (PET). Z01115 exhibited good binding affinity (Ki=25.4±5.1nM) to hB1R. 68Ga-Z01115 was prepared in 74±5 decay-corrected radiochemical yield with >99% radiochemical purity and 155±89GBq/µmol (4.2±2.4Ci/µmol) specific activity. 68Ga-Z01115 was stable in vitro in mouse plasma (93% remaining intact after 60min incubation), and relatively stable in vivo (51±5% remaining intact at 5min post-injection). PET imaging and biodistribution studies in mice showed that 68Ga-Z01115 cleared rapidly from nontarget tissues/organs, and generated high target-to-nontarget contrast images. The uptake of 68Ga-Z01115 in B1R-positive (B1R+) tumor was 5.65±0.59%ID/g at 1h post-injection. Average contrast ratios of B1R+ tumor-to-B1R- tumor, -to-blood and -to-muscle were 24.3, 24.4 and 82.9, respectively. Uptake of 68Ga-Z01115 in B1R+ tumors was reduced by ∼90% with co-injection of cold standard, confirming it was mediated by B1R. Our data suggest that 68Ga-Z01115 is a promising tracer for imaging the expression of B1R that is overexpressed in a variety of cancers.

Analysis of complexes of metabolites with europium tetracycline using capillary electrophoresis coupled with laser-induced luminescence detection.

Glycolysis and Krebs cycle intermediates were incubated with Eu3+-tetracycline and separated using capillary electrophoresis utilizing post-column laser-induced luminescence detection in a sheath flow cuvette. 3-phopshoglycerate, phosphoenolpyruvate, adenosine diphosphate, phosphate, citrate and oxaloacetate were detected at a concentration of 100 µM or lower. When all these detected metabolites were contained within the same sample it was found that they interfered with one another. Of all the metabolites, oxaloacetate showed the highest detectability. The system was found to yield a linear response for oxaloacetate from 50 nM to 10 µM. The injected volume of sample was 400 pL. This corresponds to 2 × 10-17 mol of injected oxaloacetate from the 50 nM sample. As an application, the system was used to assay the enzyme aspartate aminotransferase, for whom oxaloacetate is a product. After a 1 h incubation period, 1.2 × 10-13 M (3.3 µU/mL) enzyme was sufficient to form a detectable product signal. Extension of this incubation to 18 h permitted the detection of the activity of 1.2 × 10-14 M (330 nU/mL) enzyme. This is the equivalent of 4.8 ymoles (2.9 molecules) of enzyme in the 400 pL injection volume. The enzyme's catalytic rate was determined to be 240 s-1 under the conditions used. In a second application, homogenates of Drosophila melanogaster were analyzed for metabolites, providing several peaks, including one which had the same retention time as citrate.

Influence of iron on modulation of the antioxidant system in rat brains exposed to lead.

The objective of this study was to evaluate markers of oxidative stress in the brains of rats exposed to lead acetate (Pb(C2 H3 O2 )2 ), either associated or not associated with ferrous sulfate (FeSO4 ). A total of 36 weaning rats (Rattus norvegicus) were divided into 6 groups of six animals and exposed to lead acetate for six weeks. In the control group (control), the animals received deionized water. The Pb260 and Pb260 + Fe received 260 µM lead acetate, and the Pb1050 and Pb1050 + Fe received 1050 µM lead acetate. The Pb260 + Fe and Pb1050 + Fe were supplemented with 20 mg of ferrous sulfate/Kg body weight every 2 days. Group Fe received deionized water and ferrous sulfate. The rat brains were collected to analyze the enzymatic activity of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and the concentration of reduced glutathione (GSH), lipid peroxidation (TBARS), and total antioxidant substance (TAS) (DPPH• technique). The activity of SOD and GPx in the experimental groups decreased compared to the control, together with the concentration of GSH (p < 0.05). For CAT analysis, SOD tended to increase in concentration in the experimental groups without a concomitant exposure to FeSO4 , whereas GPx showed a slight tendency to increase in activity compared to the control. For TAS-DPPH• , there was a decrease in the experimental groups (p < 0.05). According to the results, SOD, GPx, and GSH were affected by lead acetate and exposure to ferrous sulfate changed this dynamic. However, further studies are needed to verify whether ferrous sulfate acts as a protectant against the toxic effects of lead. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 813-822, 2017.

Occurrence and Fate of Organic and Organometallic Pollutants in Municipal Wastewater Treatment Plants and Their Impact on Receiving Waters (Adour Estuary, France).

To achieve a "Good Environmental Status by 2015," as demanded by the water framework directive, monitoring programs are needed to furnish data on target compounds. In this study, a first evaluation of influents and main emissions of 3 local wastewater treatment plants (WWTP) in the Adour estuary (southwest of France) was performed for 23 pollutants (10 musk fragrances, 5 alkylphenols, and 8 organometallics), as well as receiving estuarine water from the same area. High frequency of occurrence of these compounds was found in influents samples (musks: 22-100%; alkylphenols 11-100%; organometallics 0-100%) and effluents (musks: 0-100%; alkylphenols 0-100%; organometallics 0-100%). The removal efficiencies were calculated and varied from negative values up to 98% with the lowest values for synthetic musk compounds. Temporal variability of the target compounds also was studied, and a few tendencies were observed. Estimation of the daily output of each WWTP into the estuary also showed that galaxolide, nonylphenol, monobuthyltin, and inorganic mercury were the compounds discharged into the environment at the highest concentrations. Finally, the occurrence of these compounds in estuarine waters was evaluated; most of them were present at concentrations below the limits of quantification (musks: 0.53-41.5 ng/L; alkylphenols 3.4-410 ng/L; organometallics 0.02-0.70 ng/L) suggesting a low impact in the resulting receiving waters.

Transition Metal-based Anticancer Drugs Targeting Nucleic Acids: A Tandem Mass Spectrometric Investigation.

The search for effective drugs against cisplatin-resistant tumors resulted in a large number of organometallic compounds that are evaluated for their antiproliferative activity. Among the most promising candidates are bent metallocenes based on various transition metal ions and ligands. The elucidation of structural features and the characterization of the interaction of a drug candidate with its target require accurate and sensitive analytical tools. Tandem mass spectrometry is applied to the investigation of the adduct sites and binding patterns of metallodrugs bound to single-stranded oligonucleotides and higher-order nucleic acids. Results reveal the binding specificities of the different metallodrugs and demonstrate the influence they exert on the dissociation pathways of the adducts in the gas-phase.

Elemental bioimaging of thulium in mouse tissues by laser ablation-ICPMS as a complementary method to heteronuclear proton magnetic resonance imaging for cell tracking experiments.

Due to the fact that cellular therapies are increasingly finding application in clinical trials and promise success by treatment of fatal diseases, monitoring strategies to investigate the delivery of the therapeutic cells to the target organs are getting more and more into the focus of modern in vivo imaging methods. In order to monitor the distribution of the respective cells, they can be labeled with lanthanide complexes such as thulium-1,4,7,10-tetraazacyclodoecane-α,α,α,α-tetramethyl-1,4,7,10-tetraacetic acid (Tm(DOTMA)). In this study, experiments on a mouse model with two different cell types, namely, tumor cells and macrophages labeled with Tm(DOTMA), were performed. The systemic distribution of Tm(DOTMA) of both cell types was investigated by means of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS). Using the high resolution of 25 µm, distribution maps of Tm in different tissues such as tumor, liver, lung, and spleen as well as in explanted gel pellets were generated and the behavior of the labeled cells inside the tissue was investigated. Additionally, quantitative data were obtained using homemade matrix-matched standards based on egg yolk. Using this approach, limits of detection and quantification of 2.2 and 7.4 ng·g(-1), respectively, and an excellent linearity over the concentration range from 0.01 to 46 µg·g(-1) was achieved. The highest concentration of the label agent, 32.4 µg·g(-1), in tumor tissue was observed in the area of the injection of the labeled tumor cells. Regarding the second experiment with macrophages for cell tracking, Tm was detected in the explanted biogell pellet with relatively low concentrations below 60 ng·g(-1) and in the liver with a relatively high concentration of 10 µg·g(-1). Besides thulium, aluminum was detected with equal distribution behavior in the tumor section due to a contamination resulting from the labeling procedure, which includes the usage of an Al electrode.

Metal carbonyl vapor generation coupled with dielectric barrier discharge to avoid plasma quench for optical emission spectrometry.

The scope of dielectric barrier discharge (DBD) microplasma as a radiation source for optical emission spectrometry (OES) is extended by nickel carbonyl vapor generation. We proved that metal carbonyl completely avoids the extinguishing of plasma, and it is much more suitable for matching the DBD excitation and OES detection with respect to significant DBD quenching by concomitant hydrogen when hydride generation is used. A concentric quartz UV reactor allows sample solution to flow through the central channel wherein to efficiently receive the uniformly distributed UV irradiation in the confined cylindrical space between the concentric tubes, which facilitates effective carbonyl generation in a nickel solution. The carbonyl is transferred into the DBD excitation chamber by an argon stream for nickel excitation, and the characteristic emission of nickel at 232.0 nm is detected by a charge-coupled device (CCD) spectrometer. A 1.0 mL sample solution results in a linear range of 5-100 µg L(-1) along with a detection limit of 1.3 µg L(-1) and a precision of 2.4% RSD at 50 µg L(-1). The present DBD-OES system is validated by nickel in certified reference materials.

Sensitive MRI detection of internalized T1 contrast agents using magnetization transfer contrast.

This work addresses the possibility of using Magnetization Transfer Contrast (MTC) for an improved MRI detection of T1 relaxation agents. The need to improve the detection threshold of MRI agents is particularly stringent when the contrast agents failed to accumulate to the proper extent in targeting procedures. The herein reported approach is based on the T1 dependence of MT contrast. It has been assessed that MT contrast can allow the detection of a Gd-containing agent at a lower detection threshold than the one accessible by acquiring T1W images. Measurements have been carried out either in TS/A cells or in vivo in a syngeneic murine breast cancer model. The reported data showed that in cellular experiments the MTC method displays a better sensitivity with respect to the common T1W experiments. In particular, the reached detection threshold allowed the visualization of samples containing only 2% of Gd-labeled cells diluted in unlabeled cells. In vivo experiments displayed a more diversified scheme. In particular, the tumor region showed two distinct behaviors accordingly with the localization of the imaging probe. The probe located in the tumor core could be detected to the same extent either by T1w or MTC contrast. Conversely, the agent located in the tumor rim was detected with a larger sensitivity by the MTC method herein described.

Distribution of temperature changes and neurovascular coupling in rat brain following 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") exposure.

(+/-)3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") is an abused psychostimulant that produces strong monoaminergic stimulation and whole-body hyperthermia. MDMA-induced thermogenesis involves activation of uncoupling proteins (UCPs), primarily a type specific to skeletal muscle (UCP-3) and absent from the brain, although other UCP types are expressed in the brain (e.g. thalamus) and might contribute to thermogenesis. Since neuroimaging of brain temperature could provide insights into MDMA action, we measured spatial distributions of systemically administered MDMA-induced temperature changes and dynamics in rat cortex and subcortex using a novel magnetic resonance method, Biosensor Imaging of Redundant Deviation in Shifts (BIRDS), with an exogenous temperature-sensitive probe (thulium ion and macrocyclic chelate 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethyl-1,4,7,10-tetraacetate (DOTMA(4-))). The MDMA-induced temperature rise was greater in the cortex than in the subcortex (1.6 ± 0.4 °C versus 1.3 ± 0.4 °C) and occurred more rapidly (2.0 ± 0.2 °C/h versus 1.5 ± 0.2 °C/h). MDMA-induced temperature changes and dynamics in the cortex and body were correlated, although the body temperature exceeded the cortex temperature before and after MDMA. Temperature, neuronal activity, and blood flow (CBF) were measured simultaneously in the cortex and subcortex (i.e. thalamus) to investigate possible differences of MDMA-induced warming across brain regions. MDMA-induced warming correlated with increases in neuronal activity and blood flow in the cortex, suggesting that the normal neurovascular response to increased neural activity was maintained. In contrast to the cortex, a biphasic relationship was seen in the subcortex (i.e. thalamus), with a decline in CBF as temperature and neural activity rose, transitioning to a rise in CBF for temperature above 37 °C, suggesting that MDMA affected CBF and neurovascular coupling differently in subcortical regions. Considering that MDMA effects on CBF and heat dissipation (as well as potential heat generation) may vary regionally, neuroprotection may require different cooling strategies.