Retrieval and reconsolidation of object recognition memory are independent processes in the perirhinal cortex.

Reconsolidation refers to the destabilization/re-stabilization process upon memory reactivation. However, the parameters needed to induce reconsolidation remain unclear. Here we evaluated the capacity of memory retrieval to induce reconsolidation of object recognition memory in rats. To assess whether retrieval is indispensable to trigger reconsolidation, we injected muscimol in the perirhinal cortex to block retrieval, and anisomycin (ani) to impede reconsolidation. We observed that ani impaired reconsolidation in the absence of retrieval. Therefore, stored memory underwent reconsolidation even though it was not recalled. These results indicate that retrieval and reconsolidation of object recognition memory are independent processes.

Role of major histocompatibility complex and ethnicity in acute renal graft rejection.

BACKGROUND: The major histocompatibility complex (MHC) plays a main role in antigen presentation. Class I, II, and III genes form defined "blocks" of conserved DNA sequences (conserved extended haplotypes) that are useful to follow the ancestry of a population. Each variant encodes a specific peptide that determines a particular individual's immune response. In addition, differential expression of HLA antigens in certain physiological and pathological conditions may participate in the pathogenesis of allograft rejection versus tolerance. OBJECTIVES: The aim of this study was to determine whether the specific HLA ancestry was associated with acute renal graft rejection among the Mexican mestizo population. MATERIALS AND METHODS: We studied 544 Mexican mestizo renal donors and their respective recipients for their serologically determined HLA and based on antigens haplotype assignments. The acute rejection group was compared with the nonrejection group among donors and recipients, correspondingly. RESULTS: Frequent Mexican alleles were observed in this study. Moreover, HLA-B*61/-DR*04, HLA-A*35/-DR*06 (Amerindian ancestry), HLA-A*68/-DR*01, HLA-A*28/-B*65/-DR*01 (African ancestry), and HLA-A*33/-B*65 (Caucasian ancestry) in donors were associated with acute renal graft rejection episodes. CONCLUSION: Knowing the ancestry of a donor's HLA molecules may help to individualize immunosuppressive therapy for posttransplant surveillance, because they may be more membrane-exposed in parenchymal cells, making them more susceptible of being recognized by the recipient's immune system.

Siparuna guianensis Aublet (negramina): uma revisão / Siparuna guianensis Aublet (negramina): a review

As pesquisas realizadas a partir de recursos genéticos de espécies medicinais nativas somente serão aplicadas se o material genético estiver seguro quanto à sobrevivência e disponibilidade. O objetivo deste artigo foi realizar uma revisão bibliográfica adotando como critério a escolha de artigos publicados em conceituadas revistas nacionais e internacionais, que permitissem melhor entendimento dos aspectos etnobotânicos, ecológicos e químicos de importante planta medicinal e aromática: Siparuna guianensis Aublet. Como tem sido apontada como uma das espécies prioritárias de conservação para a região do cerrado brasileiro, os estudos da propagação devem ser incentivados para que este recurso genético esteja disponível às gerações futuras.

Studies with genetic resources of native medicinal species will only be applied if their genetic material is safe regarding survival and availability. The aim of this study was to do a literature review adopting as criterion the choice of papers published in renowned national and international journals to allow better understanding on ethnobotanical, ecological and chemical aspects of an important medicinal and aromatic plant, Siparuna guianensis Aublet. Since the latter has been considered one of the major species for the conservation of Brazilian cerrado, studies on its propagation should be encouraged in order to make this genetic resource available to future generations.

Basolateral amygdala glutamatergic activation enhances taste aversion through NMDA receptor activation in the insular cortex.

In conditioned taste aversion (CTA), a subject learns to associate a novel taste with visceral malaise. Brainstem, limbic and neocortical structures have been implicated in CTA memory formation. Nevertheless, the role of interactions between forebrain structures during these processes is still unknown. The present experiment was aimed at investigating the possible interaction between the basolateral nucleus of the amygdala (BLA) and the insular cortex (IC) during CTA memory formation. Injection of a low dose of lithium chloride (30 mg/kg, i.p.) 30 min after novel taste consumption (saccharin 0.1%) induces a weak CTA. Unilateral BLA injection of glutamate (2 microg in 0.5 microL) just before low lithium induces a stronger CTA. Unilateral injection of an N-methyl-d-aspartate (NMDA) receptor antagonist (AP5, 5 microg in 0.5 microL) in IC has no effect. However, AP5 treatment in IC at the same time or 1 h after the ipsilateral BLA injection reverses the glutamate-induced CTA enhancement. Injection of AP5 in IC 3 h after BLA injection does not interfere with the glutamate effect. Moreover, the CTA-enhancing effect of glutamate was also blocked by contralateral IC injection of AP5 at the same time. These results provide strong evidence that NMDA receptor activation in the IC is essential to enable CTA enhancement induced by glutamate infusion in the BLA during a limited time period that extends to 1 but not to 3 hours. These findings indicate that BLA-IC interactions regulate the strength of CTA. The bilateral nature of these amygdalo-cortical interactions is discussed.