Human autoinflammatory disease reveals ELF4 as a transcriptional regulator of inflammation.

Transcription factors specialized to limit the destructive potential of inflammatory immune cells remain ill-defined. We discovered loss-of-function variants in the X-linked ETS transcription factor gene ELF4 in multiple unrelated male patients with early onset mucosal autoinflammation and inflammatory bowel disease (IBD) characteristics, including fevers and ulcers that responded to interleukin-1 (IL-1), tumor necrosis factor or IL-12p40 blockade. Using cells from patients and newly generated mouse models, we uncovered ELF4-mutant macrophages having hyperinflammatory responses to a range of innate stimuli. In mouse macrophages, Elf4 both sustained the expression of anti-inflammatory genes, such as Il1rn, and limited the upregulation of inflammation amplifiers, including S100A8, Lcn2, Trem1 and neutrophil chemoattractants. Blockade of Trem1 reversed inflammation and intestine pathology after in vivo lipopolysaccharide challenge in mice carrying patient-derived variants in Elf4. Thus, ELF4 restrains inflammation and protects against mucosal disease, a discovery with broad translational relevance for human inflammatory disorders such as IBD.

New quinolone derivatives as neuropeptide S receptor antagonists: Design, synthesis, homology modeling, dynamic simulations and modulation of Gq/Gs signaling pathways.

In a search for new neuropeptide S receptor antagonists, we have described a new series of quinolone-pyranopyrimidine hybrid derivatives aiming to modify the inhibitory characters towards NPSR to develop new therapeutic strategies against anxiety, addiction and food disorders. We identified six potent antagonists 3, 4b, 6, 8, 9 and 10 which counteracted the stimulatory effect of NPS at both Gq and Gs pathways, at low micromolar concentrations, through modulation of Ca2+ and cAMP signaling, respectively. Molecular docking predicted the orientation mode of the top active compounds; 10 and 4b with ΔG value of -23.94 and -23.87 kcal/mol, respectively that is considered good when compared to that of the reference compound ML154 (ΔG = -25.75 kcal/mol) . Molecular dynamic simulations confirmed the stability of binding of compound 10 to the homology model of NPSR as it reached the equilibrium after 4 ns at RMSD of 1.00 Å while ML154 was faster to achieve the equilibrium after 2 ns at RMSD of 1.00 Å.

Human PI3Kγ deficiency and its microbiota-dependent mouse model reveal immunodeficiency and tissue immunopathology.

Phosphatidylinositol 3-kinase-gamma (PI3Kγ) is highly expressed in leukocytes and is an attractive drug target for immune modulation. Different experimental systems have led to conflicting conclusions regarding inflammatory and anti-inflammatory functions of PI3Kγ. Here, we report a human patient with bi-allelic, loss-of-function mutations in PIK3CG resulting in absence of the p110γ catalytic subunit of PI3Kγ. She has a history of childhood-onset antibody defects, cytopenias, and T lymphocytic pneumonitis and colitis, with reduced peripheral blood memory B, memory CD8+ T, and regulatory T cells and increased CXCR3+ tissue-homing CD4 T cells. PI3Kγ-deficient macrophages and monocytes produce elevated inflammatory IL-12 and IL-23 in a GSK3α/ß-dependent manner upon TLR stimulation. Pik3cg-deficient mice recapitulate major features of human disease after exposure to natural microbiota through co-housing with pet-store mice. Together, our results emphasize the physiological importance of PI3Kγ in restraining inflammation and promoting appropriate adaptive immune responses in both humans and mice.

Draft Genome Sequence of a Highly Heterozygous Yeast Strain from the Metschnikowia pulcherrima Subclade, UCD127.

Metschnikowia strain UCD127 was isolated from soil in Ireland and sequenced. It is a highly heterozygous diploid strain with 385,000 single nucleotide polymorphisms (SNPs). Its ribosomal DNA has the highest similarity to that of M. chrysoperlae, but its ACT1 and TEF1 loci and mitochondrial genome show affinity to those of M. fructicola, whose genome is significantly larger.

Neuroprotective activity of macamides on manganese-induced mitochondrial disruption in U-87 MG glioblastoma cells.

Macamides are a distinct class of secondary metabolites, benzylamides of long chain fatty acids, which were isolated from the Peruvian plant Lepidium meyenii (Maca). As structural analogues of the endocannabinoid anandamide (AEA), they have demonstrated neuroprotective effects in vitro and in vivo. The purpose of this study was to demonstrate the neuroprotective activity of the macamides: N-(3-methoxybenzyl)oleamide (MAC 18:1), N-(3-methoxybenzyl)linoleamide (MAC 18:2) and N-(3-methoxybenzyl)linolenamide (MAC 18:3) in a neurotoxic environment caused by exposure of U-87 MG glioblastoma cells to manganese chloride (MnCl2). The neuroprotective effects of these macamides were reversed by the CB1 antagonist AM251. The mechanism by which manganese (Mn) induces cell damage was investigated by studying its effects on mitochondria. Reactive oxygen species (ROS) increase intracellular calcium and enhance the opening of mitochondrial permeability transition pores (MPTP), which leads to decreased mitochondrial membrane potential (MMP), to disruption of mitochondria and to neuron death in neurodegenerative disorders. In this study, MnCl2 at 50µM was responsible for mitochondrial disruption, which was attenuated by all three of the macamides tested. Human peroxisome proliferator-activated receptor gamma (PPARγ) has been proposed to be a cannabinoid target, and PPARγ has also been demonstrated to mediate some of the longer-term vascular effects of the plant cannabinoid, ∆9-tetrahydrocannabinol. PPARγ activation was observed in response to exposures of cells to MAC 18:2 and MAC 18:3. These findings suggest that macamides achieve their neuroprotective effects by binding to CB1 receptors to protect against Mn-induced toxicity in U-87 MG glioblastoma cells. Additionally these macamides, in a manner similar to the analogous endocannabinoid AEA, interact with other targets such as PPARγ to regulate metabolism and energy homeostasis, cell differentiation and inflammation.

High Concentrations of Rosiglitazone Reduce mRNA and Protein Levels of LRP1 in HepG2 Cells.

Low-density lipoprotein receptor-related protein 1 (LRP1) is an endocytic receptor involved in the uptake of a variety of molecules, such as apoE, α2-macroglobulin, and the amyloid ß peptide (Aß), for either transcellular transport, protein trafficking or lysosomal degradation. The LRP1 gene can be transcribed upon activation of peroxisome proliferator receptor activated-γ (PPARγ) by the potent PPARγ agonist, rosiglitazone (RGZ). In previous studies, RGZ was shown to upregulate LRP1 levels in concentrations between 0.1 and 5 µM in HepG2 cells. In this study, we sought to replicate previous studies and to investigate the molecular mechanism by which high concentrations of RGZ reduce LRP1 levels in HepG2 cells. Our data confirmed that transcriptional activation of LRP1 occurred in response to RGZ at 3 and 10 µM, in agreement with the study reported by Moon et al. (2012a). On the other hand, we found that high concentrations of RGZ decreased both mRNA and protein levels of LRP1. Mechanistically, transcriptional dysregulation of LRP1 was affected by the downregulation of PPARγ in a time- and concentration-dependent manner. However, downregulation of PPARγ was responsible for only 40% of the LRP1 reduction and thereby the remaining loss of LRP1 (60%) was found to be through degradation in the lysosomal system. In conclusion, our findings demonstrate the mechanisms by which high concentrations of RGZ caused LRP1 levels to be reduced in HepG2 cells. Taken together, this data will be helpful to better explain the pharmacological modulation of this pivotal membrane receptor by PPARγ agonists.

Coumarinyl pyranopyrimidines as new neuropeptide S receptor antagonists; design, synthesis, homology and molecular docking.

In this work, we described the design, synthesis and characterization of a new class of NPSR antagonists bearing the tetracyclic coumarinyl pyranopyrimidine scaffold incorporated with different acyclic and/or heterocyclic moieties. These compounds are highlighted in this study as never being used as NPSR antagonists before which provides a model for the discovery of new bioactive inhibitors that may hold potential for drug development towards anxiety, food, and addiction disorders. Synthetic and medicinal chemistry studies led to the identification of four potent antagonists, compounds 7d, 10, 12 and 13, which were able to significantly inhibit the stimulatory effect of NPS through counteracting the increased intracellular Ca2+ accumulation. The target compound 7d was the most active derivative behaving as a pure NPSR antagonist and displaying IC50 value of 2 µM. Homology model of NPSR was built based on bovine rhodopsin structure. Modeling studies were carried out to further rationalize the NPSR binding mode of the target compounds. Moreover, molecular dynamics simulation study was performed for compounds 7d, 10 and 12 which revealed the stability of the ligand-protein complex and the reliability of the docking studies.

New Coumarin Derivatives as Anti-Breast and Anti-Cervical Cancer Agents Targeting VEGFR-2 and p38α MAPK.

Breast and cervical cancers are the most common gender-specific cancers affecting women worldwide. In this investigation, we highlighted the synthesis, VEGFR-2 and p38α MAPK inhibitory activity of new series of fluorinated coumarin-based derivatives featuring a variety of bioactive chemical moieties attached or fused to the coumarin nucleus at the 3 and/or 4 position. The bioactive inhibitors were further assessed for their anti-proliferative effect against human MCF-7 breast cancer and HeLa cervical cancer cell lines, respectively. Most of the tested compounds showed potent preferential inhibition effects against human VEGFR-2 and remarkable anticancer activities in the human breast cancer cell line MCF-7. Compounds 29, 24, and 2 displayed the highest inhibitory activity against VEGFR-2 (94% inhibition) and they were the most potent anticancer agents toward MCF-7 cancer cells with IC50 values of 7.90, 8.28, and 8.30 µg/mL, respectively. Compound 13 inhibited p38α MAPK phosphorylation with a significant reduction in % cell viability against HeLa cancer cells at 10 and 30 µM. Docking experiments carried out on VEGFR-2 and p38 MAPK crystallographic structures revealed that the active compounds bind to the active sites through H-bonds, arene-cation, and hydrophobic π-π interactions. QSAR analysis demonstrated considerable correlation coefficient (R2 = 0.76969) and root mean square error (RMSE = 0.10446) values. Also, the residual values between the experimental pIC50 and predicted pIC50 are very close, indicating the reliability of the established QSAR model.

Dietary Crude Lecithin Increases Systemic Availability of Dietary Docosahexaenoic Acid with Combined Intake in Rats.

Crude lecithin, a mixture of mainly phospholipids, potentially helps to increase the systemic availability of dietary omega-3 polyunsaturated fatty acids (n-3 PUFA), such as docosahexaenoic acid (DHA). Nevertheless, no clear data exist on the effects of prolonged combined dietary supplementation of DHA and lecithin on RBC and plasma PUFA levels. In the current experiments, levels of DHA and choline, two dietary ingredients that enhance neuronal membrane formation and function, were determined in plasma and red blood cells (RBC) from rats after dietary supplementation of DHA-containing oils with and without concomitant dietary supplementation of crude lecithin for 2-3 weeks. The aim was to provide experimental evidence for the hypothesized additive effects of dietary lecithin (not containing any DHA) on top of dietary DHA on PUFA levels in plasma and RBC. Dietary supplementation of DHA-containing oils, either as vegetable algae oil or as fish oil, increased DHA, eicosapentaenoic acid (EPA), and total n-3 PUFA, and decreased total omega-6 PUFA levels in plasma and RBC, while dietary lecithin supplementation alone did not affect these levels. However, combined dietary supplementation of DHA and lecithin increased the changes induced by DHA supplementation alone. Animals receiving a lecithin-containing diet also had a higher plasma free choline concentration as compared to controls. In conclusion, dietary DHA-containing oils and crude lecithin have synergistic effects on increasing plasma and RBC n-3 PUFA levels, including DHA and EPA. By increasing the systemic availability of dietary DHA, dietary lecithin may increase the efficacy of DHA supplementation when their intake is combined.

Modulation of inducible nitric oxide synthase (iNOS) expression and cardiovascular responses during static exercise following iNOS antagonism within the ventrolateral medulla.

Previous reports indicate that inducible nitric oxide synthase (iNOS) blockade within the rostral ventrolateral medulla (RVLM) and caudal ventrolateral medulla (CVLM) differentially modulated cardiovascular responses, medullary glutamate, and GABA concentrations during static skeletal muscle contraction. In the current study, we determined the role of iNOS antagonism within the RVLM and CVLM on cardiovascular responses and iNOS protein expression during the exercise pressor reflex in anesthetized rats. Following 120 min of bilateral microdialysis of a selective iNOS antagonist, aminoguanidine (AGN; 10 µM), into the RVLM, the pressor responses were attenuated by 72 % and changes in heart rate were reduced by 38 % during a static muscle contraction. Furthermore, western blot analysis of iNOS protein abundance within the RVLM revealed a significant attenuation when compared to control animals. In contrast, bilateral administration of AGN (10 µM) into the CVLM augmented the increases in mean arterial pressure by 60 % and potentiated changes in heart rate by 61 % during muscle contractions, but did not alter expression of the iNOS protein within the CVLM. These results demonstrate that iNOS protein expression within the ventrolateral medulla is differentially regulated by iNOS blockade that may, in part, contribute to the modulation of cardiovascular responses during static exercise.

Effects of medullary administration of a nitric oxide precursor on cardiovascular responses and neurotransmission during static exercise following ischemic stroke.

We have reported that in rats with a 90 min left middle cerebral artery occlusion (MCAO) and 24 h reperfusion, pressor responses during muscle contractions were attenuated, as were glutamate concentrations in the left rostral ventrolateral medulla (RVLM) and left caudal VLM (CVLM), but gamma-aminobutyric acid (GABA) levels increased in left RVLM and CVLM. This study determined the effects of L-arginine, a nitric oxide (NO) precursor, within the RVLM and (or) CVLM on cardiovascular activity and glutamate/GABA levels during static exercise in left-sided MCAO rats. Microdialysis of L-arginine into left RVLM had a greater attenuation of cardiovascular responses, a larger decrease in glutamate, and a significant increase in GABA levels during muscle contractions in stroke rats. Administration of N(G)-monomethyl-L-arginine, an NO-synthase inhibitor, reversed the effects. In contrast, L-arginine administration into left CVLM evoked a greater potentiation of cardiovascular responses, increased glutamate, and decreased GABA levels during contractions in stroked rats. However, L-arginine administration into both left RVLM and left CVLM elicited responses similar to its infusion into the left RVLM. These results suggest that NO within the RVLM and CVLM modulates cardiovascular responses and glutamate/GABA neurotransmission during static exercise following stroke, and that a RVLM-NO mechanism has a dominant effect in the medullary regulation of cardiovascular function.

Macamides and their synthetic analogs: evaluation of in vitro FAAH inhibition.

Maca (Lepidium meyenii), a traditional food crop of the Peruvian Andes is now widely touted as a dietary supplement. Among the various chemical constituents isolated from the plant are a unique series of non-polar, long-chain fatty acid N-benzylamides known as macamides. We have synthesized 11 of the 19 reported macamides and have tested each as potential inhibitors of the human enzyme, fatty acid amide hydrolase (FAAH). The five most potent macamides were FAAH inhibitors (IC50=10-17µM). These amides were derivatives of oleic, linoleic and linolenic acids and benzylamine or 3-methoxybenzylamine. Of the three compounds evaluated in a pre-incubation time study, two macamides were not irreversible inhibitors of FAAH. The third, a carbamate structurally related to macamides, was shown to be an irreversible inhibitor of FAAH (IC50=0.153µM).

The macamide N-3-methoxybenzyl-linoleamide is a time-dependent fatty acid amide hydrolase (FAAH) inhibitor.

The Peruvian plant Lepidium meyenii (Maca) has been shown to possess neuroprotective activity both in vitro and in vivo. Previous studies have also demonstrated the activity of the pentane extract and its macamides, the most representative lipophilic constituents of Maca, in the endocannabinoid system as fatty acid amide hydrolase (FAAH) inhibitors. One of the most active macamides, N-3-methoxybenzyl-linoleamide, was studied to determine its mechanism of interaction with FAAH and whether it has inhibitory activity on mono-acyl glycerol lipase (MAGL), the second enzyme responsible for endocannabinoid degradation. Macamide concentrations from 1 to 100 µM were tested using FAAH and MAGL inhibitor assay methods and showed no effect on MAGL. Tests with other conditions were performed in order to characterize the inhibitory mechanism of FAAH inhibition. N-3-methoxybenzyl-linoleamide displayed significant time-dependent and dose-dependent FAAH inhibitory activity. The mechanism of inhibition was most likely irreversible or slowly reversible. These results suggest the potential application of macamides isolated from Maca as FAAH inhibitors, as they might act on the central nervous system to provide analgesic, anti-inflammatory, or neuroprotective effects, by modulating the release of neurotransmitters.

Comparative study of equimolar doses of gamma-hydroxybutyrate (GHB), 1,4-butanediol (1,4-BD) and gamma-butyrolactone (GBL) on catalepsy after acute and chronic administration.

Gamma-hydroxybutyrate (GHB), and its precursors 1,4-butanediol (1,4-BD) and gamma-butyrolactone (GBL) are known drugs of abuse. The ability of acute and chronic administration of equimolar doses of GHB (200mg/kg), 1,4-BD (174mg/kg) and GBL (166mg/kg) to produce catalepsy in male Swiss Webster mice was examined. GHB, 1,4-BD, GBL produced catalepsy when injected acutely. Drug treatment was then continued for 14days. Tolerance development was determined on days 6, 14, and challenged with a higher dose on day 15 in those chronically pretreated mice, and compared with naïve mice. Chronic GHB produced tolerance to catalepsy, as evidenced from area under the curve (AUC) of catalepsy versus time (min-sec) on days 6 (678±254), 14 (272±247), which were less than those on day 1 (1923±269). However, less tolerance was seen from GBL or 1,4-BD, as AUCs on days 6 and 14 were not significantly lower than that of day 1. In conclusion, although equimolar doses were used, expecting similar levels of GHB in the body, 1,4-BD and GBL shared only some of the in vivo effects of GHB. The rate of metabolic conversion of 1,4-BD and GBL into GHB might be responsible for the differences in the tolerance development to these drugs.

Neurobehavioral effects of lead and manganese individually and in combination in developmentally exposed rats.

The behavioral effects of exposure to environmentally relevant low levels of the known neurotoxicants lead (Pb) and manganese (Mn) are of current interest, especially when exposure occurs in the period of early development. The incidence of real life neurodevelopmental toxicity is dependent on co-exposure to multiple neurotoxicants present in the environment, and it is therefore important to study these in combination. Pregnant rats were given ad libitum access to drinking water solutions containing Pb (10 µg/mL), Mn (2mg/mL) or a mixture, from beginning of gestation, through lactation and until weaning. Metal-exposed pups were born with significantly higher body weights compared to controls. While female pups exposed to metal mixtures displayed the highest body weights through two months of age, differences were not significant among male pups after the first week. Mixture-exposed pups exhibited the fastest righting times when tested between postnatal days (PNDs) 1 and 10. Learning and memory were assessed in five-day Morris water maze (MWM) tests, ending in probe trials on PNDs 25 and 60. On PND 24, mixture-exposed males performed significantly better than individual metal-exposed males, but this effect was no longer evident between PNDs 56 and 60. Females exposed to Pb or Mn displayed deficits at both behavioral time points. In the open-field test, Mn-exposed males were hypoactive and displayed greater anxiety than controls on PND 24, and showed similar trends when the test was repeated on PND 59. No such differences were observed in female pups or in pups exposed to metal mixture. Metal levels analyzed in blood, brain and milk samples suggested a pharmacokinetic interaction between Pb and Mn. Therefore, developmental exposures to low levels of Pb and Mn can produce gender-specific neurobehavioral deficits, and this study underlines the importance of studying toxicants in combination.

Iron-responsive olfactory uptake of manganese improves motor function deficits associated with iron deficiency.

Iron-responsive manganese uptake is increased in iron-deficient rats, suggesting that toxicity related to manganese exposure could be modified by iron status. To explore possible interactions, the distribution of intranasally-instilled manganese in control and iron-deficient rat brain was characterized by quantitative image analysis using T1-weighted magnetic resonance imaging (MRI). Manganese accumulation in the brain of iron-deficient rats was doubled after intranasal administration of MnCl(2) for 1- or 3-week. Enhanced manganese level was observed in specific brain regions of iron-deficient rats, including the striatum, hippocampus, and prefrontal cortex. Iron-deficient rats spent reduced time on a standard accelerating rotarod bar before falling and with lower peak speed compared to controls; unexpectedly, these measures of motor function significantly improved in iron-deficient rats intranasally-instilled with MnCl(2). Although tissue dopamine concentrations were similar in the striatum, dopamine transporter (DAT) and dopamine receptor D(1) (D1R) levels were reduced and dopamine receptor D(2) (D2R) levels were increased in manganese-instilled rats, suggesting that manganese-induced changes in post-synaptic dopaminergic signaling contribute to the compensatory effect. Enhanced olfactory manganese uptake during iron deficiency appears to be a programmed "rescue response" with beneficial influence on motor impairment due to low iron status.

Transcranial focused ultrasound to the thalamus is associated with reduced extracellular GABA levels in rats.

OBJECTIVE: Transcranial focused ultrasound (FUS), with its ability to non-invasively modulate the excitability of region-specific brain areas, is gaining attention as a potential neurotherapeutic modality. The aim of this study was to examine whether or not FUS administered to the brain could alter the extracellular levels of glutamate and γ-aminobutyric acid (GABA), which are representative excitatory and inhibitory amino acid neurotransmitters, respectively. METHODS: FUS, delivered in the form of a train of pulses, was applied to the thalamus of Sprague-Dawley rats transcranially. Glutamate and GABA were directly sampled from the frontal lobe of the rat brain via a direct microdialysis technique before, during, and after the sonication. The dialysate concentrations were determined by high-performance liquid chromatography. RESULTS: The individual levels of the neurotransmitters sampled were normalized to the baseline level for each rat. In terms of the changes in extracellular glutamate levels, there was no difference between the FUS-treated group and the unsonicated control group. However, extracellular GABA levels started to decrease upon sonication and remained reduced (approximately 20% below baseline; repeated-measures ANOVA, p < 0.05, adjusted for multiple comparisons) compared to the control group. CONCLUSION: The ability to modulate region-specific brain activity, along with the present evidence of the ability to modulate neurotransmission, demonstrates the potential utility of FUS as a completely new non-invasive therapeutic modality.

Plasma choline concentration varies with different dietary levels of vitamins B6, B12 and folic acid in rats maintained on choline-adequate diets.

Choline is an important component of the human diet and is required for the endogenous synthesis of choline-containing phospholipids, acetylcholine and betaine. Choline can also be synthesised de novo by the sequential methylation of phosphatidylethanolamine to phosphatidylcholine. Vitamins B6, B12 and folate can enhance methylation capacity and therefore could influence choline availability not only by increasing endogenous choline synthesis but also by reducing choline utilisation. In the present experiment, we determined whether combined supplementation of these B vitamins affects plasma choline concentration in a rat model of mild B vitamin deficiency which shows moderate increases in plasma homocysteine. To this end, we measured plasma choline and homocysteine concentrations in rats that had consumed a B vitamin-poor diet for 4 weeks after which they were either continued on the B vitamin-poor diet or switched to a B vitamin-enriched diet for another 4 weeks. Both diets contained recommended amounts of choline. Rats receiving the B vitamin-enriched diet showed higher plasma choline and lower plasma homocysteine concentrations as compared to rats that were continued on the B vitamin-poor diet. These data underline the interdependence between dietary B vitamins and plasma choline concentration, possibly via the combined effects of the three B vitamins on methylation capacity.

Effects of inducible nitric oxide synthase blockade within the periaqueductal gray on cardiovascular responses during mechanical, heat, and cold nociception.

We have examined the role of inducible nitric oxide synthase (iNOS) within the dorsolateral periaqueductal gray mater (dlPAG) on cardiovascular responses during mechanical, thermal, and cold nociception in anesthetized rats. Mechanical stimulus was applied by a unilateral hindpaw pinch for 10 s that increased mean arterial pressure (MAP) and heart rate (HR). Bilateral microdialysis of a selective iNOS inhibitor, aminoguanidine (AGN; 10 µM), into the dlPAG for 30 min augmented MAP and HR responses during a mechanical stimulation. The cardiovascular responses recovered following discontinuation of the drug. Heat stimulus was generated by immersing one hindpaw metatarsus in a water bath at 52°C for 10 s, and this increased MAP and HR. Administration of AGN into the PAG potentiated these cardiovascular responses. Cardiovascular responses recovered following discontinuation of the drug. In contrast, application of a cold stimulus by immersing one hindpaw at 10°C for 10 s resulted in depressor and bradycardic responses. A second cold stimulus resulted in a response that was not significantly different from that prior to or after recovery from the AGN infusion. These results demonstrate that iNOS within the dlPAG plays a differential role in modulating cardiovascular responses during mechanical-, heat-, and cold-mediated nociception.

Severe postnatal iron deficiency alters emotional behavior and dopamine levels in the prefrontal cortex of young male rats.

Iron deficiency in early human life is associated with abnormal neurological development. The objective of this study was to evaluate the effect of postnatal iron deficiency on emotional behavior and dopaminergic metabolism in the prefrontal cortex in a young male rodent model. Weanling, male, Sprague-Dawley rats were fed standard nonpurified diet (220 mg/kg iron) or an iron-deficient diet (2-6 mg/kg iron). After 1 mo, hematocrits were 0.42 ± 0.0043 and 0.16 ± 0.0068 (mean ± SEM; P < 0.05; n = 8), liver nonheme iron concentrations were 2.3 ± 0.24 and 0.21 ± 0.010 µmol/g liver (P < 0.05; n = 8), and serum iron concentrations were 47 ± 5.4 and 23 ± 7.1 µmol/L (P < 0.05; n = 8), respectively. An elevated plus maze was used to study emotional behavior. Iron-deficient rats displayed anxious behavior with fewer entries and less time spent in open arms compared to control rats (0.25 ± 0.25 vs. 1.8 ± 0.62 entries; 0.88 ± 0.88 vs. 13 ± 4.6 s; P < 0.05; n = 8). Iron-deficient rats also traveled with a lower velocity in the elevated plus maze (1.2 ± 0.15 vs. 1.7 ± 0.12 cm/s; P < 0.05; n = 8), behavior that reflected reduced motor function as measured on a standard accelerating rotarod device. Both the time on the rotarod bar before falling and the peak speed attained on rotarod by iron-deficient rats were lower than control rats (156 ± 12 vs. 194 ± 12 s; 23 ± 1.5 vs. 28 ± 1.6 rpm; P < 0.05; n = 7-8). Microdialysis experiments showed that these behavioral effects were associated with reduced concentrations of extracellular dopamine in the prefrontal cortex of the iron-deficient rats (79 ± 7.0 vs. 110 ± 14 ng/L; P < 0.05; n = 4). Altered dopaminergic signaling in the prefrontal cortex most likely contributes to the anxious behavior observed in young male rats with severe iron deficiency.