Critical phases of the brain development

Various effects were shown to act alter the proceeding of histogenetic processes in the embryonic neural tissue. Studies in mice revealed that, depending on the embryogenesis stage when a lack of serotonin occurred, the lack of this monoamine entails either death of the embryo or a teratogenic effect, or underdevelopment of brain structures. In the rat model of a shorten hypoxia, a disorder of neural tissue histogenesis in early stages of development, was found, as well as a reduction of its sensitivity to lack of oxygen by the end of embryogenesis.     

An overview of malaria transmission from the perspective of Amazon Anopheles vectors

In the Americas, areas with a high risk of malaria transmission are mainly located in the Amazon Forest, which extends across nine countries. One keystone step to understanding the Plasmodium life cycle in Anopheles species from the Amazon Region is to obtain experimentally infected mosquito vectors. Several attempts to colonise Ano- pheles species have been conducted, but with only short-lived success or no success at all. In this review, we review the literature on malaria transmission from the perspective of its Amazon vectors. Currently, it is possible to develop experimental Plasmodium vivax infection of the colonised and field-captured vectors in laboratories located close to Amazonian endemic areas. We are also reviewing studies related to the immune response to P. vivax infection of Anopheles aquasalis, a coastal mosquito species. Finally, we discuss the importance of the modulation of Plasmodium infection by the vector microbiota and also consider the anopheline genomes. The establishment of experimental mosquito infections with Plasmodium falciparum, Plasmodium yoelii and Plasmodium berghei parasites that could provide interesting models for studying malaria in the Amazonian scenario is important. Understanding the molecular mechanisms involved in the development of the parasites in New World vectors is crucial in order to better determine the interaction process and vectorial competence.     

Morphometric and electrophysiologic research on the parafascicular complex of the thalamus in early ontogeny in the rabbit

Electrophysiological, morphometric and behavioural studies have been made on the role of parafascicular complex in regulation of nociceptive sensitivity in 45 rabbits from the 1st to the 16th day of their postnatal life. The evoked potential to nociceptive stimulation was recorded already in 1-day animals. Analysis of amplitude-temporal parameters of the EPs in acute experiments revealed a sharp increase in their positive phase at the 7-8th day of life. As it was shown in the behavioural experiments, that is just the period of maximum generalized reaction to nociceptive stimulation. It was found that to this age, the surface of neurones in the complex significantly increases, their density remaining still high. The data obtained are discussed in relation to factors which account for ontogenetic changes in electrophysiological correlates of neuronal responses in the parafascicular complex to peripheral nociceptive stimulation.     

Genetic diversity of chloroquine-resistant Plasmodium vivax parasites from the western Brazilian Amazon

The molecular basis of Plasmodium vivax chloroquine (CQ) resistance is still unknown. Elucidating the molecular background of parasites that are sensitive or resistant to CQ will help to identify and monitor the spread of resistance. By genotyping a panel of molecular markers, we demonstrate a similar genetic variability between in vitro CQ-resistant and sensitive phenotypes of P. vivax parasites. However, our studies identified two loci (MS8 and MSP1-B10) that could be used to discriminate between both CQ-susceptible phenotypes among P. vivax isolates in vitro. These preliminary data suggest that microsatellites may be used to identify and to monitor the spread of P. vivax-resistance around the world.     

Effect of positive and negative emotional states on the electrical activity of the auditory cortex in rabbit ontogeny

It has been shown that in all age groups of animals, self-stimulation of the hypothalamus is accompanied with the decrease in the latent period and the increase in the amplitude of the evoked potential (EP) in the auditory cortex. During negative stimulation, the increase in temporal parameters of the response takes place together with the decrease in the amplitude of the EP and the onset of secondary waves. Significant age changes were revealed in the recovery of the initial pattern of the EP after cessation of stimulation of emotiogenic zones. The recovery of the EP after stimulation of the "reward" zone in younger rabbits occurs 4 times faster than in adult animals, whereas in the former the recovery period of the EP after stimulation of the "punishment" zone is significantly longer.