AZP2006, a new promising treatment for Alzheimer's and related diseases.

Progranulin (PGRN) is a protein with multiple functions including the regulation of neuroinflammation, neuronal survival, neurite and synapsis growth. Although the mechanisms of action of PGRN are currently unknown, its potential therapeutic application in treating neurodegenerative diseases is huge. Thus, strategies to increase PGRN levels in patients could provide an effective treatment. In the present study, we investigated the effects of AZP2006, a lysotropic molecule now in phase 2a clinical trial in Progressive Supranuclear Palsy patients, for its ability to increase PGRN level and promote neuroprotection. We showed for the first time the in vitro and in vivo neuroprotective effects of AZP2006 in neurons injured with Aß1-42 and in two different pathological animal models of Alzheimer's disease (AD) and aging. Thus, the chronic treatment with AZP2006 was shown to reduce the loss of central synapses and neurons but also to dramatically decrease the massive neuroinflammation associated with the animal pathology. A deeper investigation showed that the beneficial effects of AZP2006 were associated with PGRN production. Also, AZP2006 binds to PSAP (the cofactor of PGRN) and inhibits TLR9 receptors normally responsible for proinflammation when activated. Altogether, these results showed the high potential of AZP2006 as a new putative treatment for AD and related diseases.

Nitric oxide and sleep in the rat: a puzzling relationship.

To date, only a few studies indicate that nitric oxide may play a role in the regulation of the sleep-wake cycle. However, data reported are controversial and the part played by nitric oxide in sleep-wake cycle regulation still remains uncertain. In the present report, we studied the effects on sleep amounts of two different nitric oxide synthase inhibitors: N-nitro-L-arginine methyl ester, a non-selective nitric oxide synthase inhibitor, and 7-nitro-indazole, a specific inhibitor of neuronal nitric oxide synthase. The above compounds were administered via two routes, i.e. intraperitoneally or locally in the dorsal raphe nucleus, a structure involved in sleep regulation. In order to evaluate their efficiency to inhibit nitric oxide synthesis in the rat brain, they were first administered intraperitoneally to a group of animals, and the cortical release of nitric oxide was determined by means of voltammetric measurements. N-Nitro-L-arginine methyl ester (100 mg/kg, i.p.) did not affect the cortical release of nitric oxide, whereas it increased both slow-wave sleep and paradoxical sleep durations. On the contrary, 7-nitro-indazole (40 mg/kg, i.p.) significantly decreased the cortical release of nitric oxide (-25%) and paradoxical sleep duration. Furthermore, following microinjection of either N-nitro-L-arginine methyl ester or 7-nitro-indazole at 100 ng/0.20 microl into the nitric oxidergic cell area of the dorsal raphe nucleus, decreases in paradoxical sleep duration were obtained (-32.8% and -25.3%, respectively). The results obtained support the existence of a duality in the sleep regulation modalities exerted by nitric oxide, i.e. a peripheral inhibiting influence and a central facilitating role for the nitric oxide-serotoninergic neurons of the dorsal raphe nucleus.

Voltammetric detection of nitric oxide (NO) in the rat brain: its variations throughout the sleep-wake cycle.

A sensor allowing the specific detection of nitric oxide (NO) is reported. Together with differential pulsed voltammetry, it allows the detection of a 650 mV signal either in NO solutions or in the rat frontal cortex. The intraperitoneal (i.p.) administration of a NO donor (S-nitrosoglutathione, 20 mg/kg i.p.) increases the signal height (+30%) while that of a nitric oxide synthase (NOS) inhibitor like L-nitro-arginine-p-nitro-anilide (100 mg/kg i.p.), produces its complete disappearance in the cortex of anesthetized rats. These results suggest that the 650 mV signal might be NO-dependent. Some other NOS inhibitors have been found either inefficient (L-nitro-arginine-methyl-ester) or partially efficient (7-nitro-indazole) on the signal height. In freely moving rats, also equipped with polygraphic electrodes, the signal measured in the frontal cortex exhibits the highest height during waking. It decreases during slow-wave sleep (-6%) and paradoxical sleep (-9%).

Localization of nitric oxide-synthesizing neurons sending projections to the dorsal raphe nucleus of the rat.

The origin of the nerve fibers immunoreactive for neuronal nitric oxide synthase (nNOS) in the rat dorsal raphe nucleus (DRN) was determined by combining the use of cholera toxin subunit b (CTb) as a retrograde tracer and nNOS immunohistochemistry with a monoclonal anti-nNOS antibody. Double labeled CTb-nNOS cell bodies were distributed from the rostral diencephalon to the caudal medulla oblongata, in about 20 areas of the brain. Several of the areas displaying double labeled cells are known for their involvement in the control of the sleep-wake cycle and/or transmission of nociception.

[Influence of cerebral and peripheral nitric oxide on sleep/wake cycle in the rat]. / Influences de l'oxyde nitrique (NO) cérébral et périphérique sur le cycle veille/sommeil du rat.

Through a polygraphic and pharmacological approach conducted in the rat, it is established that L-NAME (N-nitro-L-arginine methyl ester; an inhibitor of the endothelial and neuronal NO-synthases), administered intraperitoneally (i.p., 100 mg/kg) increases significantly slow wave sleep (SWS) and paradoxical sleep (PS). On the contrary, 7-NI (7-Nitro-indazole; an inhibitor of the neuronal NO-synthase), when administered locally in the nRD (n. raphe dorsalis), decreases PS without SWS changes. Finally, SIN-1 (molsidomine, a NO donor), also administered locally in the nRD (200 ng/0.2 microliter), increases PS without effects on SWS. According to the fact that L-NAME is not efficient on the cerebral NO fraction when administered i.p., it appears likely that this compound, mainly through its vascular effects, might inhibit SWS and PS. On the contrary, the effects, respectively inhibitory and facilitatory, observed on PS after nRD local injection of 7-NI and SIN-1 1 indicate that the NO-ergic component of this nucleus might facilitate PS.

Cortical and pontine variations occurring in the voltammetric no signal throughout the sleep-wake cycle in the rat.

Voltammetric measurements of nitric oxide (NO) were performed either in the frontal cortex (Cx) or in the nucleus raphe dorsalis (nRD) of rats equipped for polygraphic recordings. In the frontal cortex, the 650 mV signal related to NO exhibited its highest height during the waking state (W) and decreased slightly during slow-wave sleep (SWS) and even more during paradoxical sleep (PS). In the nRD, opposite variations were observed, i.e. the signal tended towards an increase during SWS and raised more consistently during PS versus W. Recordings performed either in the Cx or the nRD, throughout the light (12-h) and dark (12-h) periods, exhibited opposite nycthemeral changes, i.e. the signal height was higher in the Cx and lower in the nRD during the dark period and conversely for the light one. Paracrine and synaptic mechanisms taking place within the pons and, at least partly, also reflected in the Cx need to be further investigated.

Dual orexin actions on dorsal raphe and laterodorsal tegmentum neurons: noisy cation current activation and selective enhancement of Ca2+ transients mediated by L-type calcium channels.

The hypocretin/orexins (Hcrt/Orxs) are hypothalamic neuropeptides that regulate stress, addiction, feeding, and arousal behaviors. They depolarize many types of central neurons and can increase [Ca2+]i in some, including those of the dorsal raphe (DR) and laterodorsal tegmental (LDT) nuclei-two structures likely to contribute to the behavioral actions of Hcrt/Orx. In this study, we used simultaneous whole cell and Ca2+-imaging methods in mouse brain slices to compare the Hcrt/Orx-activated current in DR and LDT neurons and to determine whether it contributes to the Ca2+ influx evoked by Hcrt/Orx. We found Hcrt/Orx activates a similar noisy cation current that reversed near 0 mV in both cell types. Contrary to our expectation, this current did not contribute to the somatic Ca2+ influx evoked by Hcrt/Orx. In contrast, Hcrt/Orx enhanced the Ca2+ transients produced by voltage steps (-60 to -30 mV) by approximately 30% even in neurons lacking an inward current. This effect was abolished by nifedipine, augmented by Bay-K and abolished by bisindolylmaleimide I. Thus Hcrt/Orx has two independent actions: activation of noisy cation channels that generate depolarization and activation of a protein kinase C (PKC)-dependent enhancement of Ca2+ transients mediated by L-type Ca2+ channels. Immunocytochemistry verified that both these actions occurred in serotonergic and cholinergic neurons, indicating that Hcrt/Orx can function as a neuromodulator in these key neurons of the reticular activating system. Because regulation of Ca2+ transients mediated by L-channels is often linked to the control of transcriptional signaling, our findings imply that Hcrt/Orxs may also function in the regulation of long-term homeostatic or trophic processes.

Gender relations, "Hindu" nationalism, and NGO responses in India.

PIP: This article explores the strategies employed by nongovernmental organizations (NGOs) to challenge the right wing nationalism that dominates Indian politics. The opposition of the NGOs to the current political climate has evolved a variety of strategies, depending on their links with northern NGOs or international organizations such as the UN, and their reliance on foreign funding. The organizations that have links with international NGO community primarily express their opposition through consciousness raising and networking strategies. Because NGOs activities at the national level have the potential to attract the attention and anger of nationalist actors, many choose to operate at local level for fear of harassment. Some get involved in initiatives such as direct-action campaigns which spring up when violence breaks out in a locality, or immediately afterwards. Another strategy being set up by NGOs is cooperative and cross-community initiatives to encourage as well as build on historic relationships of socioeconomic and political interdependence between Hindus and Muslims. These strategies seek to strengthen people's awareness of the distinction between personal spiritual beliefs, the true character of India's composite culture, and of the religious rhetoric being disseminated by nationalist for the purpose of securing political power. Although much effort has been exerted by these organizations, these strategies have limitations, which are discussed in this paper.^ieng

5-Hydroxyindoles compounds and nitric oxide voltammetric detection in the rat brain: changes occurring throughout the sleep-wake cycle.

The release of serotonin may occur throughout the sleep-wake cycle according to 2 different modalities: - by the axonal nerve endings during waking; - by the dendrites and/or the soma of the nucleus raphe dorsalis (nRD) during sleep. Neuronal nitric oxide (NO), synthesised by constitutive NO synthase (NOS), is colocalized with neurotransmitters such as GABA, acetylcholine, somatostatin, serotonin, etc. In order to evaluate its modalities of release throughout the rat sleep-wake cycle, a sensor allowing its specific detection in freely moving animals was prepared. In the cortex, the highest NO signal occurs during the waking state (W=100%) versus slow wave sleep (SWS=-6%) and paradoxical sleep (PS=-9%). The mild variations observed might reflect a mean of the individual sleep-wake cycle variations attached to each NO source (GABAergic interneurons, cholinergic and serotoninergic axonal nerve endings, etc.).

Comparative distribution of nitric oxide synthase- and serotonin-containing neurons in the raphe nuclei of four mammalian species.

Monoclonal antibodies were generated against serotonin (5-HT) and the C-terminal portion of the neuronal form of nitric oxide synthase (nNOS), the enzyme producing nitric oxide in neurons. These antibodies were used to compare the distribution of 5-HT- and nNOS-containing neurons in the raphe nuclei of four animal species (rat, mouse, guinea pig, and cat). It was found that the rat was the only species in which the raphe nuclei contain a substantial number of nNOS-immunoreactive (IR) cell bodies. In this species and as observed by other authors, all mesencephalic raphe nuclei contained nNOS-IR cells, the largest group being located in the nucleus raphe dorsalis. The coexistence of nNOS and 5-HT immunoreactivities in these nuclei was visualized by double labeling. In the medulla, the nuclei raphe magnus and obscurus displayed a rather low number of nNOS-IR neurons. In the other species, nNOS-IR cell bodies were found in very low numbers, whatever raphe nucleus was considered. The rostral pole of the nucleus raphe dorsalis and the nuclei raphe magnus and obscurus contained a few nNOS-IR neurons which did not show any coincidence with the 5-HT neurons. In addition, nNOS-IR axons were rare. It is concluded that in the mouse, guinea pig, and cat the involvement of nitric oxide in functions subserved by 5-HT within the raphe nuclei might be minimal.

[Action duality of nitrogen oxide (NO) in experimental African trypanosomiasis]. / Dualité d'action du monoxyde d'azote (NO) dans la trypanosomose africaine expérimentale.

Patients with human African trypanosomiasis present a major dysruption of the circadian rhythmicity of the sleep-wake cycle, which was also found in rats infected with Trypanosoma brucei brucei (T.b.b.). The alterations in the immune function and nervous system in African trypsanosomiasis led us to investigate the involvement of nitric oxide (NO), a key molecule in immune and neurophysiological mechanisms, in experimental trypanosomiasis. NO was measured in 35 Sprague Dawley rats using differential impulsional voltammetry with a carbon fiber coated with porphyrin-nickel and nafion, ex vivo in the blood and in vivo in the brain. The rats were anaesthetized with sodium chlorate. Infection was performed intraperitoneally (i.p.) with 0.2 ml of a T.b.b. cryostabilate (clone AnTat 1.1E). Blood was collected by an intracardiac puncture with immediate replacement of blood volume (1 ml) in 7 control rats and 8 rats infected since 15 days, before and after i.p. administration of L-ANA (L-arginine-p-nitro-anilide, 100 mg.kg-1, an inhibitor of NO synthase). Brain measures were done in 20 rats (8 controls, and 12 rats infected since 15 or 21 days), in the cortex (H, -0.5 mm; AP, -0.8 mm; L, 1.2 mm) and the lateral ventricle (H,-3.2 mm). In infected rats, blood NO was at 70% of control values (p < 0.001), and L-ANA suppressed the NO signal in all animals (p < 0.0001), demonstrating that the signal originated from NO. Cortical NO was higher than in the ventricle in both control (p < 0.0001) and infected rats (p < 0.001). NO was more elevated in both structures in 15-day-infected rats than in control rats (p < 0.0001), the difference being enhanced in 21-day-infected rats (p < 0.001). L-ANA suppressed the NO signal in 30 to 60 min. These data suggest that NO intervenes in the development of trypanosomiasis in different manners. It is increased in the brain, which remains unexplained, where it may be involved in blood-brain barrier permeation. Conversely, it is decreased in the blood, may be because of macrophage function impairment, which would explain why trypanosomes can multiply in the host.

[Voltametric detection of cerebral NO in rats. Variations of the signal throughout the sleep-wakefulness cycle]. / Détection voltamétrique du NO cérébral chez le rat. Variations du signal à travers le cycle veille-sommeil.

Nitric oxide (NO) is synthesized in the neurons by constitutive NO synthase (NOS). Within given neuronal sets, this enzyme is colocalized with different other neurotransmitters such as, for example, GABA, acethylcholine or serotonin. Our attention has been focused on the fact that serotoninergic neurons, well known for their involvement in sleep triggering and maintenance, synthesize also NO. In order to evaluate the modalities of release of this compound throughout the rat sleep-waking cycle, we prepared a sensor allowing its specific detection in freely moving animals. The active part of this sensor is a carbon fiber (phi = 30 microns) successively coated with porphyrin nickel and nafion. In vitro, together with differential normal pulse voltammetric measurements, it allows the detection of a 650 mV signal varying linearly in NO solutions ranging from 5.10(-7) to 10(-4) M. At physiological concentrations, L-arginine, L-citrulline, nitrites and nitrates do not yield a signal at 650 mV. Similarly, the compounds administered to the animals, hydroxylamine, L-arginine p-nitroanilide (L-ANA) and L-N omega-nitro arginine methyl ester (L-NAME) are not electroactive at 650 mV. L-ANA and L-NAME, also appear to be trapping agents for NO while leaving the electrochemical properties of the sensor untouched. In vivo, in the frontal cortex of the anesthetized rat, a signal is measured at 650 mV. The administration of hydroxylamine (40 mg/kg, i.p.) induces a 100% increase in its height. The administration of L-ANA (100 mg/kg, i.p.) produces its complete disappearance within 50 min. Finally, the administration of L-NAME (100 mg/kg, i.p.) is without effect. This last aspect might be dependent upon the inability of L-NAME to cross the blood brain barrier. On the contrary, the increase in the signal height obtained with hydroxylamine and its disappearance with L-ANA support that it might depend upon NO. In vivo, and in animals also equipped with polygraphic electrodes, the signal measured in the same area of the cortex exhibits the highest height during the waking state and decreases during either slow-wave sleep (-6%) or paradoxical sleep (-9%). These mild variations might represent the mean of several NO sources (cortical GABAergic interneurons, cholinergic and serotoninergic axonal nerve endings), each of them varying differently throughout the sleep-waking cycle.