Temporal changes in mouse brain fatty acid amide hydrolase activity

Fatty acid amide hydrolase (FAAH) activity is known to mediate the tone of endogenous fatty acid amides including the endocannabinoid anandamide. FAAH is a potential therapeutic target because genetic or pharmacological ablation of FAAH promotes analgesia and anxiolytic effects without disrupting motor coordination. Little is known about the endogenous temporal fluctuations of brain FAAH activity. This is the first comprehensive study examining temporal fluctuations in mouse brain FAAH activity. Regional mouse brain homogenates were generated at the midpoint of the light (“noon”) and dark (“midnight”) cycles. While immunoblots revealed no significant changes (P>0.05) in regional activity between these two time points, in vitro activity assays detected a subtle 10% reduction (P<0.05) in cerebellar FAAH activity at midnight. A novel ex vivo autoradiography technique permitted the study of 11 different brain regions, many of which cannot be studied using traditional in vitro methods. The cerebellum and the periaqueductal gray both exhibited significant (P<0.05) reductions in regional FAAH activity in “midnight” brains. These data confirm the need to account for temporal changes in FAAH activity when therapeutically targeting FAAH.     

Comparative analysis of fatty acid amide hydrolase and cb(1) cannabinoid receptor expression in the mouse brain: evidence of a widespread role for fatty acid amide hydrolase in regulation of endocannabinoid signaling

Fatty acid amide hydrolase (FAAH) catalyses hydrolysis of the endocannabinoid arachidonoylethanolamide ("anandamide") in vitro and regulates anandamide levels in the brain. In the cerebellar cortex, hippocampus and neocortex of the rat brain, FAAH is located in the somata and dendrites of neurons that are postsynaptic to axon fibers expressing the CB(1) cannabinoid receptor [Proc R Soc Lond B 265 (1998) 2081]. This complementary pattern of FAAH and CB(1) expression provided the basis for a hypothesis that endocannabinoids may function as retrograde signaling molecules at synapses in the brain [Proc R Soc Lond B 265 (1998) 2081; Phil Trans R Soc Lond 356 (2001) 381] and subsequent experimental studies have confirmed this [Science 296 (2002) 678]. To assess more widely the functions of FAAH in the brain and the potential impact of FAAH activity on the spatiotemporal dynamics of endocannabinoid signaling in different regions of the brain, here we have employed immunocytochemistry to compare the distribution of FAAH and CB(1) throughout the mouse brain, using FAAH(-/-) mice as negative controls to validate the specificity of FAAH-immunoreactivity observed in wild type animals. In many regions of the brain, a complementary pattern of FAAH and CB(1) expression was observed, with FAAH-immunoreactive neuronal somata and dendrites surrounded by CB(1)-immunoreactive fibers. In these regions of the brain, FAAH may regulate postsynaptic formation of anandamide, thereby influencing the spatiotemporal dynamics of retrograde endocannabinoid signaling. However, in some regions of the brain such as the globus pallidus and substantia nigra pars reticulata, CB(1) receptors are abundant but with little or no associated FAAH expression and in these brain regions the spatial impact and/or duration of endocannabinoid signaling may be less restricted than in regions enriched with FAAH. A more complex situation arises in several regions of the brain where both FAAH and CB(1) are expressed but in a non-complementary pattern, with FAAH located in neurons and/or oligodendrocytes that are proximal but not postsynaptic to CB(1)-expressing axon fibers. Here FAAH may nevertheless influence endocannabinoid signaling but more remotely. Finally, there are regions of the brain where FAAH-immunoreactive neurons and/or oligodendrocytes occur in the absence of CB(1)-immunoreactive fibers and here FAAH may be involved in regulation of signaling mediated by other endocannabinoid receptors or by receptors for other fatty acid amide signaling molecules. In conclusion, by comparing the distribution of FAAH and CB(1) in the mouse brain, we have provided a neuroanatomical framework for comparative analysis of the role of FAAH in regulation of the spatiotemporal dynamics of retrograde endocannabinoid signaling in different regions of the brain.     

Immunohistochemical distribution of the cannabinoid receptor 1 and fatty acid amide hydrolase in the dog claustrum

Cannabinoid receptor 1 (CB1R) and fatty acid amide hydrolase (FAAH) are part of the endocannabinoid system (ECB) which exerts a neuromodulatory activity on different brain functions and plays a key role in neurogenesis. Although many studies have reported FAAH and CB1R expression in the brain of different animal species, to the best of our knowledge they have never been described in the canine claustrum. Claustrum samples, obtained from necropsy of four neurologically normal dogs, were formalin fixed for paraffin embedding. Sections were either stained for morpho-histological analysis or immunostained for CB1R and FAAH. Analysis of adjacent sections incubated with the two antisera showed a complementary labeling pattern in the claustrum, with CB1R antibody staining fibers while anti-FAAH antibody stained cell bodies and the proximal portion of dendrites; this particular anatomical relationship suggests a retrograde endocannabinoid action via CB1R. CB1R and FAAH complementary immunostaining and their cellular localization reported here provide the first anatomical evidence for existence of the ECB in the dog claustrum.     

Nuclear localization of Klotho in brain: an anti-aging protein

Klotho is a putative age-suppressing gene whose overexpression in mice results in extension of life span. The Klotho gene encodes a single-pass transmembrane protein whose extracellular domain is shed and released into blood, urine, and cerebrospinal fluid, potentially functioning as a humoral factor. The extracellular domain of Klotho has an activity that increases the expression of antioxidant enzymes and confers resistance to oxidative stress in cultured cells and in whole animals. The transmembrane form of the Klotho protein directly binds to multiple fibroblast growth factor receptors and modifies their ligand affinity and specificity. The purpose of the present study was to determine the precise cellular localization of Klotho in the mouse brain. Using light microscopic immunohistochemical methods, we found the highest levels of Klotho immunoreactivity in 2 brain regions: the choroid plexus, and cerebellar Purkinje cells. In the choroid plexus cells, Klotho was found not only on the plasma membrane but also in large amounts near the nuclear membrane. Likewise, in the Purkinje cell Klotho was found throughout the cell including dendrites, axon and soma with large amounts near the nuclear membrane. Using immunoelectron microscopy, we found Klotho in the cell membrane, but the highest concentration was localized in the peripheral portion of the nucleus and the nucleolus in both cell types. This new finding suggests that in addition to Klotho being secreted from cells in brain, it also has a nuclear function.     

Fatty acid amide hydrolase inhibition enhances the anti-allodynic actions of endocannabinoids in a model of acute pain adapted for the mouse

Cannabinoid ligands have been shown to be anti-nociceptive in animal models of acute and chronic pain by acting at the two known cannabinoid receptors, cannabinoid-1 receptor (CB-1) and cannabinoid-2 receptor (CB-2). A major concern with the use of cannabinoids for pain relief is that they activate receptors at sites other than those involved in the transmission of nociceptive stimuli. An alternative approach is to target the naturally occurring endocannabinoids, such as anandamide (AEA), 2-arachidonylglycerol (2-AG) and N-arachidonylglycine (N-AG). However in vivo results obtained with these compounds appear to be weak, most probably due to their rapid degradation and subsequent short half-life. The predominant enzyme responsible for the hydrolysis of anandamide (and some other endocannabinoids) in the brain is fatty acid amide hydrolase (FAAH). Recently, the alpha-ketoheterocycle OL135 has been synthesized and shown to be a highly potent and selective inhibitor of FAAH with efficacy in pain models in vivo. In the present study, we have adapted the mild thermal injury (MTI) model of acute pain for the mouse and pharmacologically characterized this model by showing significant reversal of the tactile allodynia by morphine (3, 5 and 10 mg kg(-1) s.c.), gabapentin (100 and 300 mg kg(-1) i.p.), ibuprofen (100 mg kg(-1) i.p.) and OL135 (10, 30 and 100 mg kg(-1) i.p.). Furthermore we have demonstrated, using this model, that a subtherapeutic dose of OL135 can enable the endocannabinoids AEA and 2-AG, but not N-AG to be active at doses where they are otherwise nonanalgesic (20 mg kg(-1) i.p.). The implications of this model in the study of pain in mice, and the therapeutic potential of FAAH inhibition to provide analgesia without the undesirable side effects of direct agonism of cannabinoid receptors are discussed.     

The expression of podoplanin and classic cadherins in the mouse brain

Podoplanin is a transmembrane glycoprotein indirectly linked to classic cadherins through ezrin-actin networks. Recently, the overexpression of podoplanin in high-grade malignancy brain tumors has been reported. The aim of this study was to investigate the expression of podoplanin and classic cadherins in the mouse brain. Immunohistochemistry showed that podoplanin was expressed on ependymal cells and choroid plexus epithelial cells at the ventricle side of the cell surface and at the cell-cell junctions, and on retinal pigment epithelial cells and in the pia mater; P-cadherin between choroid plexus epithelial cells and endothelial cells at the basement membrane side of cell surface, and between retinal pigment epithelial cells; VE-cadherin on the PECAM-1 positive-choroid plexus endothelial cells of the fibrovascular core; and N-cadherin on the cell surface and at the cell-cell junctions of ependymal cells, and in the pia mater. The regions expressing podoplanin, P-cadherin, and VE-cadherin did not coincide. In real-time PCR analysis, the amounts of podoplanin and P- and N-cadherin mRNA were larger in the ventricular wall with choroid plexus than in the abdominal aorta and cerebrum. In the RT-PCR analysis, the intensities of amplicon for VE-cadherin mRNA were the same for the abdominal aorta, cerebrum, and ventricular wall with the choroid plexus, suggesting that mouse ependymal cells, choroid plexus epithelial cells, and glial cells under the pia mater have the ability to express podoplanin and P- and N-cadherins. Glial cells and retinal pigment epithelial cells may create barriers by podoplanin and classic cadherins as a rate-determining step for transmission of blood components.     

Expression and glucocorticoid regulation of natriuretic peptide clearance receptor (NPR-C) mRNA in rat brain and choroid plexus

The natriuretic peptide clearance receptor (NPR-C) binds atrial natriuretic peptide, brain natriuretic peptide and C-type natriuretic peptide with high affinity. This receptor lacks an intracellular guanylate cyclase domain, and is believed to exert biological actions by sequestration of released natriuretic peptides and/or inhibition of adenylate cyclase. The present report summarizes the first detailed mapping of NPR-C mRNA in rat brain. In situ hybridization analysis revealed high levels of NPR-C mRNA expression in frontal and retrosplenial granular cortices, medial preoptic nucleus, ventral cochlear nucleus and choroid plexus. NPR-C mRNA expression was also observed in deep layers of neocortex and limbic cortex, posterior cortical amygdala, ventral subiculum, amygdalohippocampal area, and dentate gyrus. Positive hybridization signal was observed in both anterior and intermediate lobes of the pituitary gland. Regulatory studies indicated that expression of NPR-C mRNA was increased in the medial preoptic nucleus of adrenalectomized rats, suggesting negative glucocorticoid regulation. No changes in NPR-C mRNA expression were observed in frontal cortex or choroid plexus. These results suggest a role for the NPR-C in modulation of natriuretic peptide availability and/or adenylate cyclase activity in a subset of central natriuretic peptide circuits concerned with cortical, olfactory and neuroendocrine functions. Response of the NPR-C gene to changes in circulating hormones suggests the capacity for glucocorticoid modulation of natriuretic peptide action at the receptor level.     

The expression of twisted gastrulation in postnatal mouse brain and functional implications

Twisted gastrulation (TWSG1), an extracellular regulator of bone morphogenetic protein (BMP) signaling, is critical for embryonic brain development. Mice deficient in TWSG1 have abnormal forebrain development manifesting as holoprosencephaly. The expression and potential roles of TWSG1 in postnatal brain development are less well understood. We show that Twsg1 is expressed in the adult mouse brain in the choroid plexus (CP), hippocampus, and other regions, with the strongest expression observed in CP. TWSG1 was also detected in a human fetal brain at mid-gestation, with highest levels in the epithelium of CP. Bmp1, Bmp2, Bmp4–Bmp7 as well as BmprIA and BmprII, but not BmprIB, were expressed in CP. BMP antagonists Chordin (Chrd) and Noggin were not detected in CP, however Chrd-like 1 and brain-specific Chrd-like (Brorin) were expressed. Electrophysiological study of synaptic plasticity revealed normal paired-pulse facilitation and long-term potentiation in the CA1 region of hippocampus in Twsg1^−/− mice. Among the homozygous mutants that survive beyond the first 2 weeks, the prevalence of hydrocephalus was 4.3%, compared to 1.5% in a wild type colony (P=0.0133) between 3 and 10 weeks of life. We detected a high level of BMP signaling in CP in wild type adult mice that was 17-fold higher than in the hippocampus (P=0.005). In contrast, transforming growth factor beta (TGFβ) signaling was predominant in the hippocampus. Both BMP signaling and the expression of BMP downstream targets Msx1 and Msx2 were reduced in CP in Twsg1^−/− mice. In summary, we show that Twsg1 is expressed in the adult mouse and human fetal CP. We also show that BMP is a branch of TGFβ superfamily that is dominant in CP. This presents an interesting avenue for future research in light of the novel roles of CP in neural progenitor differentiation and neuronal repair, especially since TWSG1 appears to be the main regulator of BMP present in CP.     

Neuroinflammatory response of the choroid plexus epithelium in fatal diabetic ketoacidosis

A systemic inflammatory response (SIR) occurs prior to and during the treatment of severe diabetic ketoacidosis (DKA). IL-1beta, TNF-alpha and C5b-9 are components of SIR and have been speculated to be involved in the clinical brain edema (BE) of DKA. We studied IL-1beta, TNF-alpha, C5b-9, inducible nitric oxide (iNOS), ICAM-1, IL-10 and Hsp70 expression in the brains of two patients who died as the result of clinical BE during the treatment of DKA. IL-1beta was strongly expressed in the choroid plexus epithelium (CPE) and ependyma, and to a lesser extent in the hippocampus, caudate, white matter radiation of the pons, molecular layer of the cerebellum and neurons of the cortical gray matter. TNF-alpha was expressed to a lesser extent than IL-1beta, and only in the CP. C5b-9, previously shown to be deposited on neurons and oligodendrocytes, was found on CPE and ependymal cells. iNOS and ICAM-1 had increased expression in the CPE and ependyma. Hsp70 and IL-10 were also expressed in the CPE of the case with the shorter duration of treatment. Our data demonstrate the presence of a multifaceted neuroinflammatory cytotoxic insult of the CPE, which may play a role in the pathophysiology of the fatal brain edema of DKA.     

Different inflammatory reactions to vitamin D3 among the lateral, third and fourth ventricular choroid plexuses of the rat

The four choroid plexuses in the brain ventricles are not identical, but differences among them have rarely been studied. The present work concerns the inflammatory and hemorrhagic choroid plexitis produced in Lewis rats by a single gavage of cholecalciferol (vitamin D₃) or related steroids with vitamin D activity. Plexitis was very severe in the fourth ventricular plexus, somewhat less severe in the lateral ventricular plexuses, and almost absent in the third ventricular plexus. These findings were compared to the scanty data from the literature on differences among the plexuses.     

Transplantation of cultured choroid plexus epithelial cells via cerebrospinal fluid shows prominent neuroprotective effects against acute ischemic brain injury in the rat

Choroid plexus (CP) epithelial cells (CPECs) produce cerebrospinal fluid (CSF) to provide the CNS with a specialized microenvironment. Our previous study showed that the conditioned medium of cultured CPECs enhanced the survival and neurite extension of hippocampal neurons. The present study examined the ability of cultured CPECs to protect against ischemic brain injury when transplanted into the CSF. Rats were subjected to a transient occlusion of the middle cerebral artery, followed by an injection of cultured CPECs into the fourth ventricle. The injection markedly reduced neurological deficits and infarction volume within 24 h. Other beneficial effects were (1) a reduction in number of apoptotic and inflammatory cells, (2) an up-regulation of the mRNA expression of an anti-apoptotic effecter, cAMP-response element binding protein, and (3) a down-regulation of the production of pro-inflammatory factors such as interleukin-1 beta and inducible nitric oxide synthase. The injected CPECs were located within the ventricles and on the brain's surface, not in the ischemic foci, suggesting that they exert their effects by releasing diffusible neuroprotective factors into the CSF. The transplantation of CPECs via CSF is a potential new strategy for protecting against ischemic brain injury.     

Transport of [14C]hypoxanthine by sheep choroid plexus epithelium as a monolayer in primary culture: Na+-dependent and Na+-independent uptake by the apical membrane and rapid intracellular metabolic conversion to nucleotides

Hypoxanthine is the main product of purine metabolic degradation and previous studies have revealed that it is present in the sheep CSF and plasma in micromolar concentrations. The aim of this study was to elucidate the transport of this molecule across the sheep choroid plexus epithelium (CPE) as a monolayer in primary culture, to explore the mechanism of uptake by the apical side of the CPE and investigate the metabolic changes inside the cell. The estimated permeability of the CPE monolayer for [14C]hypoxanthine, [14C]adenine and [14C]guanine was low and comparable to the permeability towards the extracellular space markers. The study of [14C]hypoxanthine uptake by the CPE revealed two components: Na+-dependent and Na+-independent, the latter being partially mediated by the equilibrative nucleoside transporter 2. HPLC with simultaneous detection of radioactivity revealed that the majority of [14C]hypoxanthine inside the CPE is metabolised into [14C]nucleotides and [14C]inosine. The remaining intact [14C]hypoxanthine was transported across the opposite, basolateral side of CPE and appeared in the lower chamber buffer together with [14C]inosine. These findings indicate two possible roles of hypoxanthine uptake from the CSF by the CP epithelium in vivo: to provide material for nucleotide synthesis through the salvage pathways in the CPE, as well as to transfer excess hypoxanthine from CSF to blood.     

Effect of social isolation on CB1 and D2 receptor and fatty acid amide hydrolase expression in rats

Rearing rats in isolation has been shown to produce behavioral and neurochemical alterations similar to those observed in psychoses such as schizophrenia. Also, a dysregulation in both the endocannabinoid and dopaminergic systems has been implicated in schizophrenia. The aim of this study was to determine if there are differences in CB1 receptor and fatty acid amide hydrolase (FAAH) protein expression, as well as D2 dopamine receptor expression in different brain regions in rats reared in different environmental conditions. Twenty-one-day-old male Sprague-Dawley rats were either reared in individual cages (isolated rats) or in group cages of six per cage (group-housed rats) for 8 weeks. Quantitative fluorescence immunohistochemistry was performed on brain slices using antibodies specific to the CB1 or D2 receptor, or the enzyme FAAH. Raising rats in isolation led to a significant decrease in CB1 receptor expression in the caudate putamen and the amygdala, a significant increase in FAAH expression in the caudate putamen and the nucleus accumbens core and shell, and no significant change in D2 receptor expression in any region studied. These results indicate that the endocannabinoid system is altered in an animal model of aspects of psychosis. This implies that rearing rats under different housing conditions may provide new insight into the role of the endocannabinoid system in the development of psychoses.     

WITHDRAWN: Temporal and spatial expression patterns of laminins in ischemic adult rat brain

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at (http://www.elsevier.com/locate/withdrawalpolicy.     

Pathomorphological changes in rat brain choroid plexus due to administration of the amine-curing agent,bis(4-amino-3-methylcyclohexyl)methane

Summary Repeated oral administration of an amine-curing agent for epoxy resin, bis(4-amino-3-methylcyclohexyl)methane, gave rise to severe damage in the choroid plexus of rat brain. The damaged epithelium presented varying degrees of swelling and hydropic vacuolation on light microscopy, and varying numbers of vacuoles and inclusion bodies, frequently with lamellar structure, on transmission electron microscopy. Scanning electron microscopy of the choroid plexus disclosed some irregularity in the size of epithelial cells and occasional loss of microvilli. These changes in the choroid plexus were closely correlated with the dosage of the agent administered and the period of administration. In spite of the severe changes in the choroid plexus, no neurological abnormalities were observed in the animals during the experimental period.     

Expression of serotonin transporter mRNA in rat brain: Presence in neuronal and non-neuronal cells and effect of paroxetine

The expression of serotonin transporter mRNA in rat brain was examined by in situ hybridisation. Hybridisation was observed in cells of the known serotonergic nuclei and no other neuronal populations. It was also associated with ependymal cells of the aqueduct which may indicate a specialisation of this part of the ventricular system in anatomical and neurophysiological terms. The effect of the selective serotonin reuptake inhibitor paroxetine on neuronal expression of the serotonin tranporter mRNA was examined. Quantitation at the cellular level in the dorsal and median raphe nuclei was carried out by analysis of the mean number of silver grains per cell in autoradiographed sections. No significant change (P>0.1) in serotonin transporter mRNA expression was observed following 21 day administration of paroxetine (5 mg/kg per day).     

Expression and regulation of the fatty acid amide hydrolase gene in the rat uterus during the estrous cycle and peri-implantation period

Fatty acid amide hydrolase (FAAH) is involved in embryo development and implantation. Sex hormones down-modulate FAAH activity in the mouse uterus. However, the regulation of the FAAH gene in the uterus is unknown. Our results showed that FAAH mRNA is localized to uterine epithelial cells and circular myometrium during the estrous cycle. In ovariectomized rats, estradiol (E2) plus progesterone (P4) increased FAAH levels in both epithelial cells and circular myometrium. Interestingly, during the implantation period, FAAH mRNA was detected not only in epithelial cells and circular myometrium, but also in the primary decidual zone surrounding the implanting embryo on day 6 and in whole decidualized stromal cells on day 7. Its levels in the stromal cells were markedly higher at the implantation sites than at the inter-implantation sites on days 6 and 7. When implantation was delayed and then induced by E2 or E2 plus P4, FAAH mRNA levels were significantly increased in subepithelial stromal cells and circular myometrium, indicating that blastocyst activation and initiation of implantation in rats requires higher expression of the FAAH gene in subepithelial stromal cells and circular myometrium. In conclusion, the expression of FAAH mRNA is different in the non-pregnant and pregnant rat uterus and sex hormones up-regulate FAAH gene expression.     

Glial expression of cannabinoid CB(2) receptors and fatty acid amide hydrolase are beta amyloid-linked events in Down's syndrome

Recent data suggest that the endocannabinoid system (ECS) may be involved in the glial response in different types of brain injury. Both acute and chronic insults seem to trigger a shift in the pattern of expression of some elements of this system from neuronal to glial. Specifically, data obtained in human brain tissue sections from Alzheimer's disease patients showed that the expression of cannabinoid receptors of the CB(2) type is induced in activated microglial cells while fatty acid amide hydrolase (FAAH) expression is increased in reactive astrocytes. The present study was designed to determine the time-course of the shift from neuronal to glial induction in the expression of these proteins in Down's syndrome, sometimes referred to as a human model of Alzheimer-like beta-amyloid (Abeta) deposition. Here we present immunohistochemical evidence that both CB(2) receptors and FAAH enzyme are induced in Abeta plaque-associated microglia and astroglia, respectively, in Down's syndrome. These results suggest that the induction of these elements of the ECS contributes to, or is a result of, amyloid deposition and subsequent plaque formation. In addition, they confirm a striking differential pattern of distribution of FAAH and CB(2) receptors.     

Distribution of soluble and microsomal epoxide hydrolase in the mouse brain and its contribution to cerebral epoxyeicosatrienoic acid metabolism

Epoxide hydrolases comprise a family of enzymes important in detoxification and conversion of lipid signaling molecules, namely epoxyeicosatrienoic acids (EETs), to their supposedly less active form, dihydroxyeicosatrienoic acids (DHETs). EETs control cerebral blood flow, exert analgesic, anti-inflammatory and angiogenic effects and protect against ischemia. Although the role of soluble epoxide hydrolase (sEH) in EET metabolism is well established, knowledge on its detailed distribution in rodent brain is rather limited. Here, we analyzed the expression pattern of sEH and of another important member of the EH family, microsomal epoxide hydrolase (mEH), in mouse brain by immunohistochemistry. To investigate the functional relevance of these enzymes in brain, we explored their individual contribution to EET metabolism in acutely isolated brain cells from respective EH −/− mice and wild type littermates by mass spectrometry. We find sEH immunoreactivity almost exclusively in astrocytes throughout the brain, except in the central amygdala, where neurons are also positive for sEH. mEH immunoreactivity is abundant in brain vascular cells (endothelial and smooth muscle cells) and in choroid plexus epithelial cells. In addition, mEH immunoreactivity is present in specific neuronal populations of the hippocampus, striatum, amygdala, and cerebellum, as well as in a fraction of astrocytes. In freshly isolated cells from hippocampus, where both enzymes are expressed, sEH mediates the bulk of EET metabolism. Yet we observe a significant contribution of mEH, pointing to a novel role of this enzyme in the regulation of physiological processes. Furthermore, our findings indicate the presence of additional, hitherto unknown cerebral epoxide hydrolases. Taken together, cerebral EET metabolism is driven by several epoxide hydrolases, a fact important in view of the present targeting of sEH as a potential therapeutic target. Our findings suggest that these different enzymes have individual, possibly quite distinct roles in brain function and cerebral EET metabolism.     

The spinal precerebellar nuclei: calcium binding proteins and gene expression profile in the mouse

Sleep restriction is a widespread phenomenon, specifically in adolescents. This study investigated the impact of increasing sleep restriction in adolescents on cortisol levels and daytime sleepiness. Eighty-eight healthy adolescents were randomized to five sleep restriction protocols (four consecutive nights with 9, 8, 7, 6, or 5 h time in bed). Polysomnography (baseline and last experimental night) and multiple sleep latency test (day 6) data were obtained. Saliva cortisol levels were assessed half-hourly in the evening before and in the morning after the baseline and the last experimental night. Four nights of sleep restriction in healthy adolescents lead to a linear increase of objective sleepiness, but had no significant effect on evening or morning cortisol levels. The lack of detrimental effects of sleep restriction on cortisol levels might be due to compensation mechanisms during sleep.