Lithium activates brain phospholipase A2 and improves memory in rats: implications for Alzheimer's disease.

Phospholipase A2 (Pla2) is required for memory retrieval, and its inhibition in the hippocampus has been reported to impair memory acquisition in rats. Moreover, cognitive decline and memory deficits showed to be reduced in animal models after lithium treatment, prompting us to evaluate possible links between Pla2, lithium and memory. Here, we evaluated the possible modulation of Pla2 activity by a long-term treatment of rats with low doses of lithium and its impact in memory. Wistar rats were trained for the inhibitory avoidance task, treated with lithium for 100 days and tested for perdurability of long-term memory. Hippocampal samples were used for quantifying the expression of 19 brain-expressed Pla2 genes and for evaluating the enzymatic activity of Pla2 using group-specific radio-enzymatic assays. Our data pointed to a significant perdurability of long-term memory, which correlated with increased transcriptional and enzymatic activities of certain members of the Pla2 family (iPla2 and sPla2) after the chronic lithium treatment. Our data suggest new possible targets of lithium, add more information on its pharmacological activity and reinforce the possible use of low doses of lithium for the treatment of neurodegenerative conditions such as the Alzheimer's disease.

Conjugated linoleic acid-enriched butter improved memory and up-regulated phospholipase A2 encoding-genes in rat brain tissue.

Reduced phospholipase A2 (PLA2) activity has been reported in blood cells and in postmortem brains of patients with Alzheimer disease (AD), and there is evidence that conjugated linoleic acid (CLA) modulates the activity of PLA2 groups in non-brain tissues. As CLA isomers were shown to be actively incorporated and metabolized in the brains of rats, we hypothesized that feeding a diet naturally enriched in CLA would affect the activity and expression of Pla 2 -encoding genes in rat brain tissue, with possible implications for memory. To test this hypothesis, Wistar rats were trained for the inhibitory avoidance task and fed a commercial diet (control) or experimental diets containing either low CLA- or CLA-enriched butter for 4 weeks. After this period, the rats were tested for memory retrieval and killed for tissue collection. Hippocampal expression of 19 Pla 2 genes was evaluated by qPCR, and activities of PLA2 groups (cPLA2, iPLA2, and sPLA2) were determined by radioenzymatic assay. Rats fed the high CLA diet had increased hippocampal mRNA levels for specific PLA2 isoforms (iPla 2 g6γ; cPla 2 g4a, sPla 2 g3, sPla 2 g1b, and sPla 2 g12a) and higher enzymatic activity of all PLA2 groups as compared to those fed the control and the low CLA diet. The increment in PLA2 activities correlated significantly with memory enhancement, as assessed by increased latency in the step-down inhibitory avoidance task after 4 weeks of treatment (rs = 0.69 for iPLA2, P < 0.001; rs = 0.81 for cPLA2, P < 0.001; and rs = 0.69 for sPLA2, P < 0.001). In face of the previous reports showing reduced PLA2 activity in AD brains, the present findings suggest that dairy products enriched in cis-9, trans-11 CLA may be useful in the treatment of this disease.

Diversidade e comportamento dos insetos visitantes florais de Stachytarpheta glabra Cham. (Verbenaceae), em uma área de campo ferruginoso, Ouro Preto, MG / Richness and behavior of insect visitors of Stachytarpheta glabra Cham. (Verbenaceae), at a ferruginous field, Ouro Preto, MG, Brazil

Foi avaliada a influência de fatores abióticos e recursos florais na freqüência de visitas de insetos a Stachytarpheta glabra Cham, em uma área de campo ferruginoso, Ouro Preto, MG. Foram coletados 312 insetos visitantes pertencentes a 28 espécies. As maiores abundâncias foram as de Oxaea flavescens Klug (25 por cento), Vespidae sp1 (11,5 por cento), Vespidae sp2 (11 por cento), Antheos clorinde Hubner (10,3 por cento) e Vespidae sp3 (10 por cento). A abundância de visitantes florais acompanhou a variação dos fatores abióticos ao longo do dia (intensidade luminosa: F = 6,968, P = 0,014, r² = 0,757; temperatura: F = 7,708, P = 0,010, r² = 0,762; umidade relativa: F = 5,263, P = 0,030, r² = 0,744). O número de flores e inflorescências (rS = 0,81, n = 20, P < 0,001 e rS = 0,82, n = 20, P < 0,001, respectivamente) influenciaram a abundância de visitantes. Não houve relação significativa entre a abundância de visitantes florais e a altura das plantas. Halictidae prefere altas luminosidades e temperaturas para forragear. Abelhas grandes (Apidae e Andrenidae), ao contrário, são mais tolerantes às variações de temperatura e forrageiam praticamente durante todo o dia. Vespidae prefere altas temperaturas, porém suporta bem as variações nas taxas de luminosidade. Lepidoptera forrageia preferencialmente em luminosidade e temperatura mais altas. Os potenciais polinizadores são borboletas, mariposas, Eulaema nigrita Lepeletier e Apis mellifera L. sendo os pilhadores de S. glabra Vespidae, Halictidae, Bombus atratus Franklin e O. flavescens.

The influence of abiotic factors and floral resources on the frequency of insect visitors to Stachytarpheta glabra Cham was assessed in an area of ferruginous fields, Ouro Preto, MG. A total of 312 insects were collected, belonging to 28 species. The highest abundances were for Oxaea flavescens Klug (25 percent), Vespidae sp1 (11.5 percent), Vespidae sp2 (11 percent), Antheos clorinde Hubner (10.3 percent) and Vespidae sp3 (10 percent). There was a positive relation of abundance with light intensity (r² = 0.66, b = 0.82, P < 0.001) and temperature (r² = 0.40, b = 0.65, P = 0.001), and a negative relation with relative humidity (r² = 0.34, b = -0.60, P < 0.001). The number of flowers and inflorescences (rS = 0.81, n = 20, P < 0.001 e rS = 0.82, n = 20, P < 0.001, respectively) influenced the abundance of visits. No significant relation was found with plant height. Halictidae prefer to forage at high temperatures and light intensity. Large bees (Apidae and Andrenidae), on the other hand, are more tolerant to temperature variations and forage during the whole day. Vespidae prefer high temperatures but tolerate variation in light intensity. Lepidoptera forage preferentially during periods of high light intensity and temperature. Butterflies, moths, Eulaema nigrita Lepeleier and Apis mellifera L. are the potential pollinators whereas Vespidae, Halictidae, Bombus atratus Franklin and O. flavescens were thieves in S. glabra flowers.

Nogo CAA 3'UTR Insertion polymorphism is not associated with Schizophrenia nor with bipolar disorder.

The Nogo gene maps to 2p14-p13, a region consistently associated with schizophrenia and bipolar disorder. The association of a polymorphism in Nogo was previously investigated by two groups, with divergent results. In this report, using an alternative approach, we evaluated this same polymorphism in 725 individuals, including patients with schizophrenia, bipolar disorder, normal controls and non-human primate samples. Our results indicate that the polymorphism is not associated with any of these diseases, but has a remarkably biased distribution in ethnic groups. Genotyping of primate samples, suggest that this polymorphism is a recent event in human speciation.