Sinalização endógena do sistema Nociceptina/Orfanina FQ - receptor NOP: envolvimento na modulação da depressão experimental induzida por lipopolissacarídeo

During the last decades, it has been established that there is a relationship between major depression and activation of immune system. Nociceptin/orphanin FQ (N/OFQ) is the natural ligand of a Gi-protein coupled receptor named NOP, both compose the peptidergic system wich is involved in the regulation of mood states and inflammatory responses. Considering these actions, the present thesis aimed to investigate the consequences of blocking NOP signaling in lipopolysaccharide (LPS)-induced sickness and depressive-like behaviors in mice. Systemic administration of LPS doses, that do not cause sepsis in mice, induce changes in their behaviors related with activity of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukins 6 (IL-6) and 1β (IL-1 β). At the time points of 2 to 6 h and 24 h after intraperitoneal injection, mice treated with LPS displayed, respectively, sickness and depressive-like behaviors. In the present work the administration of LPS 0.8 mg/kg (ip) significantly induced sickness signs in Swiss and CD-1 mice, such as weight loss, transient reduction in rectal temperature and decrease of food and water intake. Moreover at 24 h after LPS injection these same mice strains displayed significantly increased immobility time on the tail suspension test (TST) when compared with control mice, this alteration was not related with possible locomotion impairments as verified on the open field test. Treatment with Nortriptyline 30 mg/kg (ip, 60 min prior the TST) reduced the immobility time of control and LPS-treated mice and was used as standard antidepressant. The NOP receptor antagonist SB-612111 (10 mg/kg, ip), 30 min prior LPS, did not modify LPS-induced sickness signs and depressive-like behavior. However, when injected 24 h after LPS treatment, SB-612111 (ip, 30 min prior the TST) as well as the peptidergic NOP receptor antagonist UFP-101 (10 nmol/2μL, icv, 5 min prior the TST) significantly reversed the toxin effects. The protocol of LPS-induced depressive-like states was also tested in NOP receptor knockout mice (NOP(-/-)) and their respective wild types (NOP(+/+)). LPS evoked transient rectal temperature reduction in NOP(-/-) mice and loss of body weight, food and water intake reduction in both NOP(+/+) and NOP(-/-) mice. The consumption of water was significantly different due to the genotype. LPS injection induced transient changes in pro-inflammatory cytokines. At 6 h after LPS injection, serum levels of TNF-α were significantly increased in NOP(+/+) and NOP(-/-) mice, as the IL-6 levels were significantly increased just in NOP(+/+) serum. At 24 h after LPS treatment the pro-inflammatory cytokines had returned to the baseline levels in both genotypes. LPS treatment elicited depressive-like effects in NOP(+/+) but not in NOP(-/-) mice. The data obtained during the execution of this doctoral thesis reveal that pharmacological and genetic blockade of NOP signaling does not affect LPS evoked sickness signs while reversing depressive-like behavior. In conclusion, these results highlight the involvement of the peptidergic system N/OFQ - NOP receptor in the modulation of behaviors related to mood and activation of the immune system.

Avaliação de duas variedades de Passiflora edulis sobre as respostas comportamentais de camundongos e um possível mecanismo de ação

The medicinal plants constitute a rich source of biologically active compounds used for the treatment of many psychiatric disorders, such as anxiety disorders and depression. Generalized anxiety disorder has increased significantly, being the second most prevalent disorder in care facilities to public health. Depression is considered a chronic and common psychiatric disorder that affects 350 million people of all ages around the world. In this context, the pharmacological intervention conduits have been employed, effective, although leave to be desired when observed adverse effects. The genus Passiflora is commonly commercially known by its fruit, but is also widely used in traditional Brazilian medicine. Passiflora edulis displays considerable morphological variability. This plant produces two types of fruit: Purple (Passiflora edulis Sims fo. edulis) and yellow (Passiflora edulis fo. flavicarpa Degener). This study investigated the central effects of aqueous extract of the leaves of the two varieties of the species Passiflora edulis in tests used to assess behavior related to anxiety and depression, as well as investigating the potential effect of the antidepressant-like fractions of edulis fo. edulis and neuropharmacological mechanisms responsible for this action. To conduct this study used male Swiss mice (2 months old, weighing 30-35 g). The animals received the aqueous extract of the leaves of the two species of Passiflora: edulis fo. edulis (100, 300, 1000 mg / kg) and fractions ethyl acetate, butanol and aqueous waste (25, 50, 75, 100 mg / kg) and edulis fo. flavicarpa (30, 100, 300, 1000 mg / kg) or saline by gavage 60 minutes prior to the maze tests at high cross the open field test, test forced swim test and sedation induced by thiopental. To investigate the mechanism of action of the activity of antidepressant type of fractions the following drugs were used: PCPA (inhibitor of 5-HT synthesis) AMPT (inhibitor of catecholamine synthesis), DSP-4 (noradrenergic neurotoxin) and Sulpiride (antagonist selective dopamine D2 receptor). They were used as a standard positive control, fluoxetine and nortriptyline. The results of the phytochemical profile show very different characteristics to the aqueous extract of the varieties of Passiflora edulis "flavicarpa" and "edulis". The aqueous extracts of both varieties of Passiflora edulis share anxiolytic activity type (edulis fo. edulis 300 mg/kg; edulis fo. flavicarpa 300 and 1000 mg/kg) and antidepressant (edulis fo. edulis 300 mg/kg; edulis fo flavicarpa 1000 mg/kg), while the effect hipolocomotor/sedative was only seen for edulis fo. edulis (1000 mg/kg). Both fractions ethyl acetate, butanol aqueous extract edulis fo. edulis showed activity type antidepressant at a dose of 50 mg/kg in the forced swim test. The data suggest that the effect of antidepressant-like fractions edulis fo. edulis involves catecholaminergic and serotonergic neurotransmission, particularly dopaminergic, there is seen that pre-treatment DSP-4 is not affected antidepressant action of fractions as was dependent activation of dopamine D2 receptors.

Avaliação de duas variedades de Passiflora edulis sobre as respostas comportamentais de camundongos e um possível mecanismo de ação

The medicinal plants constitute a rich source of biologically active compounds used for the treatment of many psychiatric disorders, such as anxiety disorders and depression. Generalized anxiety disorder has increased significantly, being the second most prevalent disorder in care facilities to public health. Depression is considered a chronic and common psychiatric disorder that affects 350 million people of all ages around the world. In this context, the pharmacological intervention conduits have been employed, effective, although leave to be desired when observed adverse effects. The genus Passiflora is commonly commercially known by its fruit, but is also widely used in traditional Brazilian medicine. Passiflora edulis displays considerable morphological variability. This plant produces two types of fruit: Purple (Passiflora edulis Sims fo. edulis) and yellow (Passiflora edulis fo. flavicarpa Degener). This study investigated the central effects of aqueous extract of the leaves of the two varieties of the species Passiflora edulis in tests used to assess behavior related to anxiety and depression, as well as investigating the potential effect of the antidepressant-like fractions of edulis fo. edulis and neuropharmacological mechanisms responsible for this action. To conduct this study used male Swiss mice (2 months old, weighing 30-35 g). The animals received the aqueous extract of the leaves of the two species of Passiflora: edulis fo. edulis (100, 300, 1000 mg / kg) and fractions ethyl acetate, butanol and aqueous waste (25, 50, 75, 100 mg / kg) and edulis fo. flavicarpa (30, 100, 300, 1000 mg / kg) or saline by gavage 60 minutes prior to the maze tests at high cross the open field test, test forced swim test and sedation induced by thiopental. To investigate the mechanism of action of the activity of antidepressant type of fractions the following drugs were used: PCPA (inhibitor of 5-HT synthesis) AMPT (inhibitor of catecholamine synthesis), DSP-4 (noradrenergic neurotoxin) and Sulpiride (antagonist selective dopamine D2 receptor). They were used as a standard positive control, fluoxetine and nortriptyline. The results of the phytochemical profile show very different characteristics to the aqueous extract of the varieties of Passiflora edulis "flavicarpa" and "edulis". The aqueous extracts of both varieties of Passiflora edulis share anxiolytic activity type (edulis fo. edulis 300 mg/kg; edulis fo. flavicarpa 300 and 1000 mg/kg) and antidepressant (edulis fo. edulis 300 mg/kg; edulis fo flavicarpa 1000 mg/kg), while the effect hipolocomotor/sedative was only seen for edulis fo. edulis (1000 mg/kg). Both fractions ethyl acetate, butanol aqueous extract edulis fo. edulis showed activity type antidepressant at a dose of 50 mg/kg in the forced swim test. The data suggest that the effect of antidepressant-like fractions edulis fo. edulis involves catecholaminergic and serotonergic neurotransmission, particularly dopaminergic, there is seen that pre-treatment DSP-4 is not affected antidepressant action of fractions as was dependent activation of dopamine D2 receptors.

Activation of Serotonin 2C Receptors in Dopamine Neurons Inhibits Binge-like Eating in Mice

This work was supported by the National Institutes of Health (Grant Nos. R01DK093587 and R01DK101379 [to YX], R01DK092605 to [QT], R01DK078056 [to MM]), the Klarman Family Foundation (to YX), the Naman Family Fund for Basic Research (to YX), Curtis Hankamer Basic Research Fund (to YX), American Diabetes Association (Grant Nos. 7-13-JF-61 [to QW] and 1-15-BS-184 [to QT]), American Heart Association postdoctoral fellowship (to PX), Wellcome Trust (Grant No. WT098012 [to LKH]), and Biotechnology and Biological Sciences Research Council (Grant No. BB/K001418/1 [to LKH]). The anxiety tests (e.g., open-field test, light-dark test, elevated plus maze test) were performed in the Mouse Neurobehavior Core, Baylor College of Medicine, which was supported by National Institutes of Health Grant No. P30HD024064. PX and YH were involved in experimental design and most of the procedures, data acquisition and analyses, and writing the manuscript. XC assisted in the electrophysiological recordings; LV-T assisted in the histology study; XY, KS, CW, YY, AH, LZ, and GS assisted in surgical procedures and production of study mice. MGM, QW, QT, and LKH were involved in study design and writing the manuscript. YX is the guarantor of this work and, as such, had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. The authors report no biomedical financial interests or potential conflicts of interest.

Le rôle des acides gras oméga-3 sur la balance énergétique, la régulation de l’appétit, l’état émotionnel et l’implication du récepteur GPR120

L’obésité est un facteur de risque lié à des problèmes physiques, émotionnels et comportementaux. Aujourd’hui, l’alimentation est composée d’un régime typiquement occidental «Western diet» qui est riche en acides gras saturés (AGS) et pauvre en acides gras polyinsaturés (AGPI) tel que les oméga-3 (N-3) et occasionnant un déséquilibre du ratio alimentaire N-6/N-3. Ce déséquilibre est une des causes de la prévalence des maladies mentales y compris celles des troubles de l'humeur et de l’anxiété. L’acide docosahexaénoïque (ADH, 22: 6 n-3) est l’acide gras (AG) le plus abondant dans le cerveau et son accumulation est particulièrement élevée pendant la période périnatale. Il joue un rôle important dans le développement neuronal et d'autres fonctions du cerveau tel l'apprentissage et la mémoire. Des perturbations de l’environnement périnatal peuvent influencer à très long terme l’avenir de la descendance en la rendant plus susceptible de développer des problèmes d’obésité dans un contexte nutritionnel riche. On ignore cependant si le déficit alimentaire chez la mère et particulièrement en ADH aura un impact sur la motivation alimentaire de la progéniture. L’objectif principal de cette thèse est d’étudier le rôle potentiel des N-3 sur la balance énergétique, la motivation alimentaire, la dépression et le niveau d’anxiété des descendants de souris mâles adultes assujetties à une alimentation riche en gras. Nos données ont démontré qu‘un régime maternel déficitaire en ADH durant la période périnatale incitait la descendance à fournir plus d’effort afin d’obtenir un aliment palatable. Ceci entraînerait un dérèglement de l’homéostasie énergétique en augmentant le gain de poids et en diminuant l’activité locomotrice tout en exacerbant le comportement de type anxieux dès que les souris sont exposées à un milieu obésogène. Les acides gras libres (AGL) sont des nutriments essentiels fonctionnant comme des molécules de signalisation dans le cerveau en ayant des récepteurs qui jouent un rôle important dans le contrôle du métabolisme énergétique. Parmi eux, on distingue un récepteur couplé à la protéine G (GPCR), le GPR120. Ce récepteur activé par les AGPI ω-3 intervient dans les mécanismes anti-inflammatoires et insulino-résistants via les N-3. Une mutation dans le gène GPR120 occasionnée par une réduction de l’activité de signalisation du gène est liée à l’obésité humaine. L'objectif premier de cette deuxième étude était d’évaluer l'impact de la stimulation pharmacologique de GPR120 dans le système nerveux central (SNC) sur l'alimentation, les dépenses d'énergie, le comportement de type anxieux et la récompense alimentaire. Nos résultats démontrent qu’une injection centrale aiguë d'agoniste GPR120 III réduit la prise alimentaire ad libitum et la motivation alimentaire pour un aliment riche en gras et en sucre; ainsi que les comportements de type anxieux. L’injection centrale chronique (21 jours) de ce même agoniste GPR120 III transmis par une pompe osmotique a démontré que les souris placées sous diète hypercalorique (HFD n’ont présenté aucune modification lors de la prise alimentaire ni de gain de poids mais qu’il y avait comparativement au groupe de véhicule, une réduction du comportement de type anxieux, que ce soit dans le labyrinthe en croix surélevé (LCS) ou dans le test à champ ouvert (OFT). L’ADH est reconnu pour ses propriétés anorexigènes au niveau central. De plus, la stimulation des récepteurs de GPR120 au niveau du cerveau avec un agoniste synthétique peut produire un effet intense intervenir sur le comportement lié à l'alimentation des rongeurs. Trouver une approche visant à contrôler à la fois la neuroinflammation, la récompense alimentaire et les troubles émotionnels aiderait assurément au traitement de l'obésité et du diabète de type 2.

The Effect of Dietary Tartrazine on Brain Dopamine and the Behavioral Symptoms of Attention Deficit Hyperactivity Disorder

Attention Deficit Hyperactivity Disorder is a neurodevelopmental disorder correlated with a decrease in brain dopamine and an increase in behavioral symptoms of hyperactivity and impulsivity. This experiment explored how tartrazine (Yellow #5) impacts these symptoms. After tartrazine administration to Spontaneously Hypertensive Rats (SHR), dopamine concentrations in regions of brain tissue were measured using Enzyme-Linked Immunosorbent Assay analysis. Behavioral testing with a T-maze and open field test measured impulsivity and hyperactivity, respectively. Results indicate that dietary tartrazine increases hyperactive behaviors in the SHR. However, results do not indicate a relationship between dietary tartrazine and brain dopamine. No conclusions regarding the relationship between dietary tartrazine and impulsivity were drawn.

Le rôle des acides gras oméga-3 sur la balance énergétique, la régulation de l’appétit, l’état émotionnel et l’implication du récepteur GPR120

L’obésité est un facteur de risque lié à des problèmes physiques, émotionnels et comportementaux. Aujourd’hui, l’alimentation est composée d’un régime typiquement occidental «Western diet» qui est riche en acides gras saturés (AGS) et pauvre en acides gras polyinsaturés (AGPI) tel que les oméga-3 (N-3) et occasionnant un déséquilibre du ratio alimentaire N-6/N-3. Ce déséquilibre est une des causes de la prévalence des maladies mentales y compris celles des troubles de l'humeur et de l’anxiété. L’acide docosahexaénoïque (ADH, 22: 6 n-3) est l’acide gras (AG) le plus abondant dans le cerveau et son accumulation est particulièrement élevée pendant la période périnatale. Il joue un rôle important dans le développement neuronal et d'autres fonctions du cerveau tel l'apprentissage et la mémoire. Des perturbations de l’environnement périnatal peuvent influencer à très long terme l’avenir de la descendance en la rendant plus susceptible de développer des problèmes d’obésité dans un contexte nutritionnel riche. On ignore cependant si le déficit alimentaire chez la mère et particulièrement en ADH aura un impact sur la motivation alimentaire de la progéniture. L’objectif principal de cette thèse est d’étudier le rôle potentiel des N-3 sur la balance énergétique, la motivation alimentaire, la dépression et le niveau d’anxiété des descendants de souris mâles adultes assujetties à une alimentation riche en gras. Nos données ont démontré qu‘un régime maternel déficitaire en ADH durant la période périnatale incitait la descendance à fournir plus d’effort afin d’obtenir un aliment palatable. Ceci entraînerait un dérèglement de l’homéostasie énergétique en augmentant le gain de poids et en diminuant l’activité locomotrice tout en exacerbant le comportement de type anxieux dès que les souris sont exposées à un milieu obésogène. Les acides gras libres (AGL) sont des nutriments essentiels fonctionnant comme des molécules de signalisation dans le cerveau en ayant des récepteurs qui jouent un rôle important dans le contrôle du métabolisme énergétique. Parmi eux, on distingue un récepteur couplé à la protéine G (GPCR), le GPR120. Ce récepteur activé par les AGPI ω-3 intervient dans les mécanismes anti-inflammatoires et insulino-résistants via les N-3. Une mutation dans le gène GPR120 occasionnée par une réduction de l’activité de signalisation du gène est liée à l’obésité humaine. L'objectif premier de cette deuxième étude était d’évaluer l'impact de la stimulation pharmacologique de GPR120 dans le système nerveux central (SNC) sur l'alimentation, les dépenses d'énergie, le comportement de type anxieux et la récompense alimentaire. Nos résultats démontrent qu’une injection centrale aiguë d'agoniste GPR120 III réduit la prise alimentaire ad libitum et la motivation alimentaire pour un aliment riche en gras et en sucre; ainsi que les comportements de type anxieux. L’injection centrale chronique (21 jours) de ce même agoniste GPR120 III transmis par une pompe osmotique a démontré que les souris placées sous diète hypercalorique (HFD n’ont présenté aucune modification lors de la prise alimentaire ni de gain de poids mais qu’il y avait comparativement au groupe de véhicule, une réduction du comportement de type anxieux, que ce soit dans le labyrinthe en croix surélevé (LCS) ou dans le test à champ ouvert (OFT). L’ADH est reconnu pour ses propriétés anorexigènes au niveau central. De plus, la stimulation des récepteurs de GPR120 au niveau du cerveau avec un agoniste synthétique peut produire un effet intense intervenir sur le comportement lié à l'alimentation des rongeurs. Trouver une approche visant à contrôler à la fois la neuroinflammation, la récompense alimentaire et les troubles émotionnels aiderait assurément au traitement de l'obésité et du diabète de type 2.

Behavioural studies on the ethanol leaf extract of Grewia carpinifolia in Wistar rats.

Background: Grewia carpinifolia is a plant commonly used in the tropics to manage various central nervous system (CNS) disorders. However, despite its widespread use no scientific work has been reported to validate these claims. Objectives: To evaluate the activity of G. carpinifolia as it affects behaviour using animal model. Methods: Twenty five adult Wistar rats were randomly divided into five groups (A-E). Group A served as control (given only distilled water), Groups B,C, D and E were administered with single oral dose of ethanol extract of G. carpinifolia leaf at 100, 200, 400 and 800 mg/kg body weight respectively for twenty eight days consecutively. Subsequently, open field test, negative geotaxis and hanging wire test were performed. Body and brain weights were measured and histological examination of the brain was also performed. Results: At the tested doses, the extract significantly increased the time spent on the hanging wire and decreased locomotor activity at 800 mg/kg. No significant difference was observed in body and brain weights of extract treated groups when compared with the control. No visible histological lesion was also observed. Conclusion: The plant extract may improve muscular strength at tested doses and possess CNS depressant activity at 800 mg/ kg.

Behavioural alterations are independent of sickness behaviour in chronic experimental Chagas disease

The existence of the nervous form of Chagas disease is a matter of discussion since Carlos Chagas described neurological disorders, learning and behavioural alterations in Trypanosoma cruzi-infected individuals. In most patients, the clinical manifestations of the acute phase, including neurological abnormalities, resolve spontaneously without apparent consequence in the chronic phase of infection. However, chronic Chagas disease patients have behavioural changes such as psychomotor alterations, attention and memory deficits, and depression. In the present study, we tested whether or not behavioural alterations are reproducible in experimental models. We show that C57BL/6 mice chronically infected with the Colombian strain of T. cruzi (150 days post-infection) exhibit behavioural changes as (i) depression in the tail suspension and forced swim tests, (ii) anxiety analysed by elevated plus maze and open field test sand and (iii) motor coordination in the rotarod test. These alterations are neither associated with neuromuscular disorders assessed by the grip strength test nor with sickness behaviour analysed by temperature variation sand weight loss. Therefore, chronically T. cruzi-infected mice replicate behavioural alterations (depression and anxiety) detected in Chagas disease patients opening an opportunity to study the interconnection and the physiopathology of these two biological processes in an infectious scenario.

Use of acoustic telemetry techniques to understand the individual variability in movement ecology of juvenile lemon sharks, Negaprion brevirostris, in natural conditions, around Bimini Islands, Bahamas: a comparison study with preliminary personality traits observed in mesocosms

Dissertação de Mestrado, Biologia Marinha, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016

Memory-enhancing effect of Rhodiola rosea L extract on aged mice

Purpose: The memory-enhancing effects of Rhodiola rosea L. extract (RRLE) on normal aged mice were assessed. Methods: In the open-field test, the effect of RRLE (150 and 300 mg/kg) on mouse locomotive activities was evaluated by investigating the extract’s influence on CAT and AchE activities in the brain tissue of mice. Results: Compared with aged group, high dose of RRLE reduced the total distance (3212.4 ± 123.1 cm, p < 0.05) significantly, increased catalase (CAT) activity (101.4 ± 12.2 U/mg pro, p < 0.05), and inhibited acetyl cholinesterase (AChE) activity (0.94 ± 0.12 U/mg pro, p < 0.05) in the brain tissue of aged mice. Conclusion: The results show that RRLE improves the memory functions of aged mice probably by increasing CAT activity while decreasing AChE activity.

Administration of cannabidiol and imipramine induces antidepressant-like effects in the forced swimming test and increases brain-derived neurotrophic factor levels in the rat amygdala

Objective: Cannabidiol is a chemical constituent from Cannabis sativa and it has multiple mechanisms of action, including antidepressant effects. The main objective of the present study was to evaluate behavioural and molecular effects induced by administration of cannabidiol and imipramine in rats. Methods: In the present study, rats were acutely or chronically treated for 14 days once a day with saline, cannabidiol (15, 30 and 60 mg/kg) or imipramine (30 mg/kg) and the animals behaviour was assessed in forced swimming and open-field tests. Afterwards, the prefrontal cortex, hippocampus and amygdala brain-derived neurotrophic factor (BDNF) levels were assessed by enzyme-linked immunosorbent sandwich assay. Results: We observed that both acute and chronic treatments with imipramine at the dose of 30 mg/kg and cannabidiol at the dose of 30 mg/kg reduced immobility time and increased swimming time; climbing time was increased only with imipramine at the dose of 30 mg/kg, without affecting locomotor activity. In addition, chronic treatment with cannabidiol at the dose of 15 mg/kg and imipramine at the dose of 30 mg/kg increased BDNF levels in the rat amygdala. Conclusion: In conclusion, our results indicate that cannabidiol has an antidepressant-like profile and could be a new pharmacological target for the treatment of major depression.

Studies on arbuscular mycorrhiza (AM) in the Alentejo (Portugal) using pea mutants resistant to AM fungi as a control tool for field conditions

The utilization and management of arbuscular mycorrhiza (AM) symbiosis may improve production and sustainability of the cropping system. For this purpose, native AM fungi (AMF) were sought and tested for their efficiency to increase plant growth by enhanced P uptake and by alleviation of drought stress. Pot experiments with safflower (Carthamus tinctorius) and pea (Pisum sativum) in five soils (mostly sandy loamy Luvisols) and field experiments with peas were carried out during three years at four different sites. Host plants were grown in heated soils inoculated with AMF or the respective heat sterilized inoculum. In the case of peas, mutants resistant to AMF colonization were used as non-mycorrhizal controls. The mycorrhizal impact on yields and its components, transpiration, and P and N uptake was studied in several experiments, partly under varying P and N levels and water supply. Screening of native AMF by most probable number bioassays was not very meaningful. Soil monoliths were placed in the open to simulate field conditions. Inoculation with a native AMF mix improved grain yield, shoot and leaf growth variables as compared to control. Exposed to drought, higher soil water depletion of mycorrhizal plants resulted in a haying-off effect. The growth response to this inoculum could not be significantly reproduced in a subsequent open air pot experiment at two levels of irrigation and P fertilization, however, safflower grew better at higher P and water supply by multiples. The water use efficiency concerning biomass was improved by the AMF inoculum in the two experiments. Transpiration rates were not significantly affected by AM but as a tendency were higher in non-mycorrhizal safflower. A fundamental methodological problem in mycorrhiza field research is providing an appropriate (negative) control for the experimental factor arbuscular mycorrhiza. Soil sterilization or fungicide treatment have undesirable side effects in field and greenhouse settings. Furthermore, artificial rooting, temperature and light conditions in pot experiments may interfere with the interpretation of mycorrhiza effects. Therefore, the myc- pea mutant P2 was tested as a non-mycorrhizal control in a bioassay to evaluate AMF under field conditions in comparison to the symbiotic isogenetic wild type of var. FRISSON as a new integrative approach. However, mutant P2 is also of nod- phenotype and therefore unable to fix N2. A 3-factorial experiment was carried out in a climate chamber at high NPK fertilization to examine the two isolines under non-symbiotic and symbiotic conditions. P2 achieved the same (or higher) biomass as wild type both under good and poor water supply. However, inoculation with the AMF Glomus manihot did not improve plant growth. Differences of grain and straw yields in field trials were large (up to 80 per cent) between those isogenetic pea lines mainly due to higher P uptake under P and water limited conditions. The lacking N2 fixation in mutants was compensated for by high mineral N supply as indicated by the high N status of the pea mutant plants. This finding was corroborated by the results of a major field experiment at three sites with two levels of N fertilization. The higher N rate did not affect grain or straw yields of the non-fixing mutants. Very efficient AMF were detected in a Ferric Luvisol on pasture land as revealed by yield levels of the evaluation crop and by functional vital staining of highly colonized roots. Generally, levels of grain yield were low, at between 40 and 980 kg ha-1. An additional pot trial was carried out to elucidate the strong mycorrhizal effect in the Ferric Luvisol. A triplication of the plant equivalent field P fertilization was necessary to compensate for the mycorrhizal benefit which was with five times higher grain yield very similar to that found in the field experiment. However, the yield differences between the two isolines were not always plausible as the evaluation variable because they were also found in (small) field test trials with apparently sufficient P and N supply and in a soil of almost no AMF potential. This similarly occurred for pea lines of var. SPARKLE and its non-fixing mycorrhizal (E135) and non-symbiotic (R25) isomutants, which were tested in order to exclude experimentally undesirable benefits by N2 fixation. In contrast to var. FRISSON, SPARKLE was not a suitable variety for Mediterranean field conditions. This raises suspicion putative genetic defects other than symbiotic ones may be effective under field conditions, which would conflict with the concept of an appropriate control. It was concluded that AMF resistant plants may help to overcome fundamental problems of present research on arbuscular mycorrhiza, but may create new ones.

Identifying the Open-Closed Field Line Boundary

Of all the various definitions of the polar cap boundary that have been used in the past, the most physically meaningful and significant is the boundary between open and closed field lines. Locating this boundary is very important as it defines which regions and phenomena are on open field lines and which are on closed. This usually has fundamental implications for the mechanisms invoked. Unfortunately, the open-closed boundary is usually very difficult to identify, particularly where it maps to an active reconnection site. This paper looks at the topological reconnection classes that can take place, both at the magnetopause and in the cross-tail current sheet and discusses the implications for identifying the open-closed boundary when reconnection is giving velocity filter dispersion of signatures. On the dayside, it is shown that the dayside boundary plasma sheet and low-latitude boundary layer precipitations are well explained as being on open field lines, energetic ions being present because of reflection of central plasma sheet ions off the two Alfvén waves launched by the reconnection site (the outer one of which is the magnetopause). This also explains otherwise anomalous features of the dayside convection pattern in the cusp region. On the nightside, similar considerations place the open-closed boundary somewhat poleward of the velocity-dispersed ion structures which are a signature of the plasma sheet boundary layer ion flows in the tail.

Antidepressant-like effects of an apolar extract and chow enriched with Nepeta cataria (catnip) in mice

Nepeta cataria (catnip) is a plant used in pet toys and to treat human diseases. Catnip has also been used in the treatment of some depressive disorders. In this paper, we studied the antidepressant, anxiogenic, and motor activity effects of acute and repeated feeding of chow enriched with 10% N. cataria leaves and the acute and repeated administration of apolar and polar extracts of N. cataria leaves in male mice. The results showed that repeated feeding and acute and repeated administration with the apolar extract reduced immobility in the behavioral despair test but did not alter elevated plus maze and open-field parameters. Acute feeding and the acute and repeated administration of the polar extracts of N. cataria leaves did not alter the behavior of mice. These data suggest that N. cataria has antidepressant properties. Moreover, this antidepressant activity was present in the apolar extract.