A recessive PRDM13 mutation results in congenital hypogonadotropic hypogonadism and cerebellar hypoplasia.

The positive regulatory (PR) domain containing 13 (PRDM13) putative chromatin modifier and transcriptional regulator functions downstream of the transcription factor PTF1A, which controls GABAergic fate in the spinal cord and neurogenesis in the hypothalamus. Here, we report a recessive syndrome associated with PRDM13 mutation. Patients exhibited intellectual disability, ataxia with cerebellar hypoplasia, scoliosis, and delayed puberty with congenital hypogonadotropic hypogonadism (CHH). Expression studies revealed Prdm13/PRDM13 transcripts in the developing hypothalamus and cerebellum in mouse and human. An analysis of hypothalamus and cerebellum development in mice homozygous for a Prdm13 mutant allele revealed a significant reduction in the number of Kisspeptin (Kiss1) neurons in the hypothalamus and PAX2+ progenitors emerging from the cerebellar ventricular zone. The latter was accompanied by ectopic expression of the glutamatergic lineage marker TLX3. Prdm13-deficient mice displayed cerebellar hypoplasia and normal gonadal structure, but delayed pubertal onset. Together, these findings identify PRDM13 as a critical regulator of GABAergic cell fate in the cerebellum and of hypothalamic kisspeptin neuron development, providing a mechanistic explanation for the cooccurrence of CHH and cerebellar hypoplasia in this syndrome. To our knowledge, this is the first evidence linking disrupted PRDM13-mediated regulation of Kiss1 neurons to CHH in humans.

Tricarboxylic acid cycle dehydrogenases inhibition by naringenin: experimental and molecular modelling evidence.

The study of polyphenols' effects on health has been gaining attention lately. In addition to reacting with important enzymes, altering the cell metabolism, these substances can present either positive or negative metabolic alterations depending on their consumption levels. Naringenin, a citrus flavonoid, already presents diverse metabolic effects. The objective of this work was to evaluate the effect of maternal naringenin supplementation during pregnancy on the tricarboxylic acid cycle activity in offspring's cerebellum. Adult female Wistar rats were divided into two groups: (1) vehicle (1 ml/kg by oral administration (p.o.)) or (2) naringenin (50 mg/kg p.o.). The offspring were euthanised at 7th day of life, and the cerebellum was dissected to analyse citrate synthase, isocitrate dehydrogenase (IDH), α-ketoglutarate dehydrogenase (α-KGDH) and malate dehydrogenase (MDH) activities. Molecular docking used SwissDock web server and FORECASTER Suite, and the proposed binding pose image was created on UCSF Chimera. Data were analysed by Student's t test. Naringenin supplementation during pregnancy significantly inhibited IDH, α-KGDH and MDH activities in offspring's cerebellum. A similar reduction was observed in vitro, using purified α-KGDH and MDH, subjected to pre-incubation with naringenin. Docking simulations demonstrated that naringenin possibly interacts with dehydrogenases in the substrate and cofactor binding sites, inhibiting their function. Naringenin administration during pregnancy may affect cerebellar development and must be evaluated with caution by pregnant women and their physicians.

Quercetin plays protective role in oxidative induced apoptotic events during chronic chlorpyrifos exposure to rats.

Chlorpyrifos (CPF), an organophosphate insecticide has a wider application throughout the world to protect agricultural crops and vegetables from insects. Polyphenolic compounds are considered as beneficial against toxicities induced by organophosphates. The present study was conducted to understand the neuroprotective role of quercetin in chlorpyrifos-induced apoptotic events in rats. Twenty-four male Sprague Dawley rats weighing 170 to 200 g were divided into four groups viz: Control, chlorpyrifos treated (13.5 mg/kg body wt. alternate day), quercetin treated (50 mg/kg body wt. every day) and combined chlorpyrifos + quercetin treated. All the treatments were carried out for a total duration of 60 days. Protein carbonyl content and acetylcholinesterase activity were estimated in serum along with cerebrum and cerebellum to ascertain neurotoxicity. Further, for appraisal of neurodegeneration as a consequence of apoptosis, protein expressions of Bcl-2, Bax, cytochrome c, caspase-8, and caspase-9 were assessed. The results showed that protein carbonyl contents were markedly increased in both serum and brain tissues (cerebrum and cerebellum) of chlorpyrifos-treated rats when compared with control group and were appreciably improved upon simultaneous supplementation with quercetin. Further, chlorpyrifos treatment revealed a significant decrease in the enzyme activity of acetylcholinesterase in serum as well as in cerebrum and cerebellum, which however was increased upon concomitant treatment with quercetin. In chlorpyrifos-treated animals, we have observed a significant decrease in the protein expression level of Bcl-2, but a remarkable increase in the expression levels of Bax, cytochrome c, caspase-8, and caspase-9 in both cerebrum and cerebellum. Interestingly, when chlorpyrifos-treated animals were supplemented with quercetin, a significant increase in the expression of Bcl-2 and an appreciable decline in the expression levels of Bax, cytochrome c, caspase-8, and caspase-9 was observed. In conclusion, the present study advocates that quercetin may prove to be a useful candidate in containing the oxidative-induced apoptotic events during chlorpyrifos exposure.

Cerebellar Ataxia and Coenzyme Q Deficiency through Loss of Unorthodox Kinase Activity.

The UbiB protein kinase-like (PKL) family is widespread, comprising one-quarter of microbial PKLs and five human homologs, yet its biochemical activities remain obscure. COQ8A (ADCK3) is a mammalian UbiB protein associated with ubiquinone (CoQ) biosynthesis and an ataxia (ARCA2) through unclear means. We show that mice lacking COQ8A develop a slowly progressive cerebellar ataxia linked to Purkinje cell dysfunction and mild exercise intolerance, recapitulating ARCA2. Interspecies biochemical analyses show that COQ8A and yeast Coq8p specifically stabilize a CoQ biosynthesis complex through unorthodox PKL functions. Although COQ8 was predicted to be a protein kinase, we demonstrate that it lacks canonical protein kinase activity in trans. Instead, COQ8 has ATPase activity and interacts with lipid CoQ intermediates, functions that are likely conserved across all domains of life. Collectively, our results lend insight into the molecular activities of the ancient UbiB family and elucidate the biochemical underpinnings of a human disease.

Inhibition of Na(+),K(+)-ATPase in the hypothalamus, pons and cerebellum of the offspring rat due to experimentally-induced maternal hypothyroidism.

Neurodevelopment is known to be particularly susceptible to thyroid hormone insufficiency and can result in extensive structural and functional deficits within the central nervous system (CNS), subsequently leading to the establishment of cognitive impairment and neuropsychiatric symptomatology. The current study evaluated the effects of gestational and/or lactational maternal exposure to propylthiouracil (PTU)-induced hypothyroidism (as a suggestive multilevel experimental approach to the study of hypothyroidism-induced changes that has been developed and characterized by the authors) on crucial brain enzyme activities of 21-day-old Wistar rat offspring in a CNS region-specific manner. The activities of acetylcholinesterase (AChE), Na(+),K(+)-ATPase and Mg(2+)-ATPase in the offspring hypothalamus, cerebellum and pons were assessed. The study demonstrated that maternal exposure to PTU (0.05% w/v in the drinking water) during the critical periods of neurodevelopment can result in an inhibition of hypothalamic, pontine and cerebellar Na(+),K(+)-ATPase; a major marker of neuronal excitability and metabolic energy production as well as an important regulator of important systems of neurotransmission. On the other hand, no significant changes in the activities of the herein offspring CNS regions' AChE and Mg(2+)-ATPase were recorded. The observed Na(+),K(+)-ATPase inhibition: (i) is region-specific (and non-detectable in whole brain homogenetes), (ii) could constitute a central event in the pathophysiology of clinically-relevant hypothyroidism-associated developmental neurotoxicity, (iii) occurs under all examined experimental schemes, and (iv) certainly deserves further clarification at a molecular and histopathological level. As these findings are analyzed and compared to the available literature, they also underline the need for the adoption and further study of Na(+),K(+)-ATPase activity as a consistent neurochemical marker within the context of a systematic comparative study of existing (and novel) simulation approaches to congenital and early age hypothyroidism.

[DYNAMICS OF GLUTAMINE SYNTHASE ACTIVITY IN RAT BRAIN IN PRENATAL HYPOXIA MODEL].

Prenatal ontogenesis is a period of high sensitivity to stressful impact, so any stressor can lead to changes of physiological, biochemical indicators, behavioral and cognitive functions. The most common and clinically significant stress factor, which the embryo may be exposed during embryonic development, is hypoxia. In this case pathological changes in the central nervous system depend on the duration and severity of hypoxic exposure, individual tolerance and the stage of prenatal development, at each of which in the brain take place the basic histogenetic processes. By activating energetically disadvantageous anaerobic glycolysis hypoxia leads to excess of glutamate emission and cell apoptosis. Glutamine synthase is a basic enzyme that regulates metabolism of glutamate, catalyzing conversion of glutamate to glutamine with ammonia detoxification. The aim of the presented work was to reveal changes in the activity of one of the key enzyme of glutamate metabolism- glutamine synthetase in the brain of offspring of white rats undergone to hypoxia at different stages of prenatal ontogenesis. Hypoxia was created by placing female rats at stages of the pregnancy, corresponding to progestation period of organogenesis and fetal period of prenatal development, in the hypobaric chamber with exposure to 5% oxygen and 95% nitrogen gas mixture during 30 minutes per day. The offspring obtained from females of control and experimental groups were used for biochemical determinations in the age of 1 and 3 month. It has been established that hypoxia exposed to pregnant females during embryonic organogenesis causes significant changes in enzyme activity, particularly pronounced in the cerebral cortex and cerebellum, as compared with progestational and fetal hypoxia. Enzyme activity decreased in a greater degree in one-month-old rats undergone to prenatal hypoxia, than three- month-old animals. Thus, stress during intensive processes of proliferation and migration of cells of the forming brain violates glutamate metabolism of the brain.

Toxicological effect of N, N, N', N'-tetramethylethylene on rat brain acetylcholinesterase.

N, N, N', N'-tetramethylethylenediamine (TEMED) is extensively used for initiating polymerization of acrylamide and bisacrylamide gel for electrophoresis and for inorganic complex structure formation. The present study evaluates the toxicological effect of TEMED on structures of rat brain acetylcholinesterase (AChE) activity. In vitro study showed that the Ki values for striatum, cortex, cerebellum and hypothalamus were found to be 1.24, 1.4, 1.45 and 1.47 mM. Kinetics studies indicated that TEMED caused mixed type of inhibition that is a combination of competitive and noncompetitive inhibition in striatum, cortex, hypothalamus and cerebellum. The result showed that km increased and V max decreased with increase in TEMED concentration. The IC50 values calculated for striatum, cortex, cerebellum and hypothalamus were found to be as 0.92, 0.92, 1.44 and 1.42 mM. The present study indicates that TEMED is a toxicant for brain via inhibition of AChE. Therefore, proper precaution should be made during its handling.

Beneficial effect of agmatine in the acute phase of experimental autoimmune encephalomyelitis in iNOS-/- knockout mice.

The aim of the study was to investigate the hypothesis that agmatine (AGM) provides protection against oxidative stress in experimental autoimmune encephalomyelitis (EAE). Wild-type (WT) and knockout (KO) CBA/H iNOS-/- 3 months old (15 ± 5 g) mice, were used for EAE induction by myelin basic protein (MBP), dissolved in Complete Freund's Adjuvant (CFA). The animals were divided into control, EAE, CFA, EAE+AGM and AGM groups. After the development of full clinical remission, animals were decapitated and oxidative stress parameters were determined in whole encephalitic mass (WEM) and cerebellum homogenates. The EAE clinical expression manifested to greater extent in WT than KO mice, was significantly decreased during AGM treatment. We demonstrated significant elevations of superoxide dismutase activity in WT and KO EAE animals, in WEM and cerebellum tissues, which were decreased during AGM treatment in both groups. Superoxide anion content was increased in WEM of both study groups, with a decrease during AGM treatment. The observed changes were more pronounced in WT than in KO animals. Also, the increased expressions of transferrin receptor and glial fibrillary acidic protein observed in WT and KO EAE mice were significantly decreased during AGM treatment. The results suggest potentially beneficial AGM effects in EAE, which might be used for a modified antioxidative approach in MS therapy.

Developmental neurotoxicity of cadmium on enzyme activities of crucial offspring rat brain regions.

Cadmium (Cd) is an environmental contaminant known to exert significant neurotoxic effects on both humans and experimental animals. The aim of this study was to shed more light on the effects of gestational (in utero) and lactational maternal exposure to Cd (50 ppm of Cd as Cd-chloride in the drinking water) on crucial brain enzyme activities in important rat offspring brain regions (frontal cortex, hippocampus, hypothalamus, pons and cerebellum). Our study provides a brain region-specific view of the changes in the activities of three crucial brain enzymes as a result of the developmental neurotoxicity of Cd. Maternal exposure to Cd during both gestation and lactation results into significant changes in the activities of acetylcholinesterase and Na(+),K(+)-ATPase in the frontal cortex and the cerebellum of the offspring rats, as well as in a significant increase in the hippocampal Mg(2+)-ATPase activity. These brain-region-specific findings underline the need for further research in the field of Cd-induced developmental neurotoxicity. Deeper understanding of the mechanisms underlying the neurodevelopmental deficits taking place due to in utero and early age exposure to Cd could shed more light on the causes of its well-established cognitive implications.

Is oxidative stress in mice brain regions diminished by 2-[(2,6-dichlorobenzylidene)amino]-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile?

2-[(2,6-Dichlorobenzylidene)amino]-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carbonitrile, 5TIO1, is a new 2-aminothiophene derivative with promising pharmacological activities. The aim of this study was to evaluate its antioxidant activity in different areas of mice central nervous system. Male Swiss adult mice were intraperitoneally treated with Tween 80 dissolved in 0.9% saline (control group) and 5TIO1 (0.1, 1, and 10 mg kg(-1)). Brain homogenates-hippocampus, striatum, frontal cortex, and cerebellum-were obtained after 24 h of observation. Superoxide dismutase and catalase activities, lipid peroxidation and nitrite content were measured using spectrophotometrical methods. To clarify the 5TIO1's mechanism on oxidative stress, western blot analysis of superoxide dismutase and catalase was also performed. 5TIO1 decreased lipid peroxidation and nitrite content in all brain areas and increased the antioxidant enzymatic activities, specially, in cerebellum. The data of Western blot analysis did not demonstrate evidence of the upregulation of these enzymes after the administration of this compound. Our findings strongly support that 5TIO1 can protect the brain against neuronal damages regularly observed during neuropathologies.

Curcumin differentially regulates the expression of superoxide dismutase in cerebral cortex and cerebellum of L-thyroxine (T4)-induced hyperthyroid rat brain.

The present investigation was aimed to elucidate the effect of curcumin on lipid peroxidation (LPx) and superoxide dismutase (SOD) in L-thyroxine (T4)-induced oxidative stress in cerebral cortex and cerebellum of rat brain. Elevated level of LPx in cerebral cortex declined to control level on supplementation of curcumin to T4-treated rats. On the other hand, unaltered LPx level in T4-treated rats showed a significantly decreased level of LPx on supplementation of curcumin. The increased activity of SOD and translated products of SOD1 and SOD2 in cerebral cortex of T4-treated rats was ameliorated on supplementation of curcumin. The decreased activity of SOD and protein expression of SOD1 in cerebellum of T4-treated rats were ameliorated on administration of curcumin. On the other hand, SOD2 expression was not influenced either by T4-treated or by curcumin supplementation to T4-treated rats. Results of the present investigation reveal that the regulation of expression of SOD by curcumin in different regions (cerebral cortex and cerebellum) of rat brain is different under hyperthyroidism.

Protective effect of Bacopa monniera on methyl mercury-induced oxidative stress in cerebellum of rats.

Methyl mercury (MeHg) is a ubiquitous environmental pollutant leading to neurological and developmental deficits in animals and human beings. Bacopa monniera (BM) is a perennial herb and is used as a nerve tonic in Ayurveda, a traditional medicine system in India. The objective of the present study was to investigate whether Bacopa monniera extract (BME) could potentially inhibit MeHg-induced toxicity in the cerebellum of rat brain. Male Wistar rats were administered with MeHg orally at a dose of 5 mg/kg b.w. for 21 days. Experimental rats were given MeHg and also administered with BME (40 mg/kg, orally) for 21 days. After the treatment period, we observed that MeHg exposure significantly inhibited the activities of superoxide dismutase, catalase, glutathione peroxidase, and increased the glutathione reductase activity in cerebellum. It was also found that the level of thiobarbituric acid-reactive substances was increased with the concomitant decrease in the glutathione level in MeHg-induced rats. These alterations were prevented by the administration of BME. Behavioral interference in the MeHg-exposed animals was evident through a marked deficit in the motor performance in the rotarod task, which was completely recovered to control the levels by BME administration. The total mercury content in the cerebellum of MeHg-induced rats was also increased which was measured by atomic absorption spectrometry. The levels of NO(2) (-) and NO(3) (-) in the serum were found to be significantly increased in the MeHg-induced rats, whereas treatment with BME significantly decreased their levels in serum to near normal when compared to MeHg-induced rats. These findings strongly implicate that BM has potential to protect brain from oxidative damage resulting from MeHg-induced neurotoxicity in rat.

N-methyl N-nitrosourea induced functional and structural alterations in mice brain-role of curcumin.

Curcumin is being widely used both as an herbal drug and a food additive in Asian countries. However, its prophylactic potential in containing certain brain disorders is yet to be fully explored. The present study was conceived with an idea that curcumin may prove to be effective in ameliorating N-methyl N-nitrosourea (MNU)-induced adverse effects in cerebrum and cerebellum of mice. Male laca mice received either intravenous MNU treatment at a dose of 10 mg/kg body weight in sterile double distilled water, curcumin alone 60 mg/kg body weight in drinking water via oral gavage, or combined MNU and curcumin treatment on alternate days for a total duration of 2 months. MNU treatment resulted in significant alteration in neurobehavior, reactive oxygen species, lipid profile and histoarchitecture which showed appreciable signs of improvements upon curcumin supplementation. Therefore, the study concludes that prophylactic treatment with curcumin shall prove to be effective in containing MNU-induced neurotoxicity.

Rescue of bilirubin-induced neonatal lethality in a mouse model of Crigler-Najjar syndrome type I by AAV9-mediated gene transfer.

Crigler-Najjar type I (CNI) syndrome is a recessively inherited disorder characterized by severe unconjugated hyperbilirubinemia caused by uridine diphosphoglucuronosyltransferase 1A1 (UGT1A1) deficiency. The disease is lethal due to bilirubin-induced neurological damage unless phototherapy is applied from birth. However, treatment becomes less effective during growth, and liver transplantation is required. To investigate the pathophysiology of the disease and therapeutic approaches in mice, we generated a mouse model by introducing a premature stop codon in the UGT1a1 gene, which results in an inactive enzyme. Homozygous mutant mice developed severe jaundice soon after birth and died within 11 d, showing significant cerebellar alterations. To rescue neonatal lethality, newborns were injected with a single dose of adeno-associated viral vector 9 (AAV9) expressing the human UGT1A1. Gene therapy treatment completely rescued all AAV-treated mutant mice, accompanied by lower plasma bilirubin levels and normal brain histology and motor coordination. Our mouse model of CNI reproduces genetic and phenotypic features of the human disease. We have shown, for the first time, the full recovery of the lethal effects of neonatal hyperbilirubinemia. We believe that, besides gene-addition-based therapies, our mice could represent a very useful model to develop and test novel technologies based on gene correction by homologous recombination.

Protective role of Cynodon dactylon in ameliorating the aluminium-induced neurotoxicity in rat brain regions.

Cynodon dactylon (Poaceae) is a creeping grass used as a traditional ayurvedic medicine in India. Aluminium-induced neurotoxicity is well known and different salts of aluminium have been reported to accelerate damage to biomolecules like lipids, proteins and nucleic acids. The objective of the present study was to investigate whether the aqueous extract of C. dactylon (AECD) could potentially prevent aluminium-induced neurotoxicity in the cerebral cortex, hippocampus and cerebellum of the rat brain. Male albino rats were administered with AlCl(3) at a dose of 4.2 mg/kg/day i.p. for 4 weeks. Experimental rats were given C. dactylon extract in two different doses of 300 mg and 750 mg/keg/day orally 1 h prior to the AlCl(3) administration for 4 weeks. At the end of the experiments, antioxidant status and activities of ATPases in cerebral cortex, hippocampus and cerebellum of rat brain were measured. Aluminium administration significantly decreased the level of GSH and the activities of SOD, GPx, GST, Na(+)/K(+) ATPase, and Mg(2+) ATPase and increased the level of lipid peroxidation (LPO) in all the brain regions when compared with control rats. Pre-treatment with AECD at a dose of 750 mg/kg b.w increased the antioxidant status and activities of membrane-bound enzymes (Na(+)/K(+) ATPase and Mg(2+) ATPase) and also decreased the level of LPO significantly, when compared with aluminium-induced rats. The results of this study indicated that AECD has potential to protect the various brain regions from aluminium-induced neurotoxicity.

ROS formation and antioxidant status in brain areas of rats exposed to sodium metavanadate.

In the present work, in vivo ROS formation and the activity of antioxidant enzymes in the hippocampus and the cerebellum of sodium metavanadate (NaVO3) treated rats were studied. Rats were i.p. injected with 3 mg/kg bw/day (V1 group) or with 7.2 mg/kg bw/day of NaVO3 (V2 group) for 5 consecutive days. Results show that after only 5 days of NaVO3 exposure, reactive oxygen species formation and alteration of the oxidative defence system were observed. Vanadium-induced OH production was detected in cerebellum at the high dose. This result was confirmed by in situ ROS histochemical staining. Neither Cat nor Cu-Zn SOD activities showed changes while GSH/GSSG ratio, in both brain areas, was significantly decreased in NaVO3-treated groups. The present work indicates that the NaVO3 dose and the particular brain area constitution would be critical in the cellular and molecular oxidative mechanism of this element.

Modulatory effect of cod-liver oil on Na(+)-K(+) ATPase in rats' brain.

Omega-3 fatty acids were used in the treatment of psychiatric diseases such as bipolar disorder. Na(+), K(+)-ATPase is also a well-known target for these fatty acids. In this study, we investigated the impact of cod-liver oil (CLO), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on Na(+), K(+)-ATPase, cholinesterase activities, the levels of norepinephrine (NE) and acetylcholine in different regions of rat brain. Our results showed that DHA caused a significant depression in cerebellum Na(+), K( +)-ATPase, whereas CLO activated it. In addition, CLO, EPA and DHA produced a significant activation in Na(+), K(+)-ATPase activity in medulla, midbrain and hypothalamus. There were non-significant changes in the activity of cholinesterase enzyme in cerebellum and medulla, while in midbrain and hypothalamus the CLO, DHA and EPA enhanced the activity by 75%, 100% and 78%, respectively. The content of NE in hypothalamus showed slight increase in different regions of the brain of animals fed CLO, DHA or EPA. In conclusion, CLO, DHA or EPA supplementation had a beneficial effect that associated with a normalization of fatty acids incorporation into phospholipid membranes and a partial restoration of Na(+), K(+)-ATPase activity, suggesting that CLO supplementation may improve fatty acid composition and moderately enhance Na(+), K(+)-ATPase activity.

Effect of natural polyphenols, pycnogenol® on superoxide dismutase and nitric oxide synthase in diabetic rats.

The work is focused on clarifying the impact of diabetes and natural plant polyphenols contained in Pycnogenol® (PYC) on the activity and synthesis of Cu/Zn-SOD and synthesis of nNOS and eNOS in the cerebellum and cerebral cortex in rats with induced diabetes. Rats included in the study (n=38) were divided into three groups: the controls (C), (n=7), untreated diabetics (D) (n=19) and diabetic rats treated with PYC (DP) (n=12). Diabetes significantly decreased synthesis, as well as the activity of Cu/Zn-SOD in both studied parts of the brain. PYC significantly increased the synthesis of Cu/Zn-SOD but had no effect on its activity. Diabetes also reduced the synthesis of nNOS in cerebral cortex and administered PYC elevated its amount to the level of controls. In the cerebellum, diabetes does not affect the synthesis of nNOS and PYC reduces synthesis of NOS. Diabetes as well as PYC had no influence on the synthesis of eNOS in both, the cerebellum and cerebral cortex. PYC modulated level of Cu/Zn-SOD and nNOS in cerebellum and cerebral cortex of diabetic rats, but in a different way.

Impact of gasoline inhalation on some neurobehavioural characteristics of male rats.

BACKGROUND: This paper examines closely and compares the potential hazards of inhalation of two types of gasoline (car fuel). The first type is the commonly use leaded gasoline and the second is the unleaded type enriched with oxygenate additives as lead substituent in order to raise the octane number. The impacts of gasoline exposure on Na+, K+-ATPase, superoxide dismutase (SOD), acetylcholinesterase (AChE), total protein, reduced glutathione (GSH), and lipid peroxidation (TBARS) in the cerebral cortex, and monoamine neurotransmitters dopamine (DA), norepinephrine (NE) and serotonin (5-HT) in the cerebral cortex, hippocampus, cerebellum and hypothalamus were evaluated. The effect of gasoline exposure on the aggressive behaviour tests was also studied. RESULTS: The present results revealed that gasoline inhalation induced significant fluctuations in the levels of the monoamine neurotransmitters in the studied brain regions. This was concomitant with a decrease in Na+, K+-ATPase activity and total protein content. Moreover, the group exposed to the unleaded gasoline exhibited an increase in lipid peroxidation and a decrease in AChE and superoxide dismutase activities. These physiological impairments were accompanied with a higher tendency towards aggressive behaviour as a consequence to gasoline inhalation. CONCLUSION: It is concluded from the present work that chronic exposure to either the leaded or the unleaded gasoline vapours impaired the levels of monoamine neurotransmitters and other biochemical parameters in different brain areas and modulated several behavioural aspects related to aggression in rats.

Development of prostaglandin endoperoxide synthase expression in the ovine fetal central nervous system and pituitary.

In this study, we tested the hypothesis that prostaglandin endoperoxide synthase-1 and -2 (PGHS-1 and PGHS-2) are expressed throughout the latter half of gestation in ovine fetal brain and pituitary. Hypothalamus, pituitary, hippocampus, brainstem, cortex and cerebellum were collected from fetal sheep at 80, 100, 120, 130, 145days of gestational age (DGA), 1 and 7days postpartum lambs, and from adult ewes (n=4-5 per group). mRNA and protein were isolated from each region, and expression of prostaglandin synthase-1 (PGHS-1) and -2 (PGHS-2) were evaluated using real-time RT-PCR and western blot. PGHS-1 and -2 were detected in every brain region at every age tested. Both enzymes were measured in highest abundance in hippocampus and cerebral cortex, and lowest in brainstem and pituitary. PGHS-1 and -2 mRNA's were upregulated in hypothalamus and pituitary after 100 DGA. The hippocampus exhibited decreases in PGHS-1 and increases in PGHS-2 mRNA after 80 DGA. Brainstem PGHS-1 and -2 and cortex PGHS-2 exhibited robust increases in mRNA postpartum, while cerebellar PGHS-1 and -2 mRNA's were upregulated at 120 DGA. Tissue concentrations of PGE(2) correlated with PGHS-2 mRNA, but not to other variables. We conclude that the regulation of expression of these enzymes is region-specific, suggesting that the activity of these enzymes is likely to be critical for brain development in the late-gestation ovine fetus.