Environmental Signals on Microglial Function during Brain Development, Neuroplasticity, and Disease.

Recent discoveries on the neurobiology of the immunocompetent cells of the central nervous system (CNS), microglia, have been recognized as a growing field of investigation on the interactions between the brain and the immune system. Several environmental contexts such as stress, lesions, infectious diseases, and nutritional and hormonal disorders can interfere with CNS homeostasis, directly impacting microglial physiology. Despite many encouraging discoveries in this field, there are still some controversies that raise issues to be discussed, especially regarding the relationship between the microglial phenotype assumed in distinct contexts and respective consequences in different neurobiological processes, such as disorders of brain development and neuroplasticity.

Serotonin transporter immunoreactivity is modulated during development and after fluoxetine treatment in the rodent visual system.

The serotonin transporter (5-HTT) regulates serotonin homeostasis and has been used as a target for different drugs in depression treatment. Although the serotonergic system has received a lot of attention, little is known about the effects of these drugs over serotonin transporters. In this work, we investigated the expression pattern of 5-HTT during development of the visual system and the influence of fluoxetine on different signaling pathways.

Intravitreous Injection of Interleukin-6 Leads to a Sprouting in the Retinotectal Pathway at Different Stages of Development.

Objective: The development of retinotectal pathways form precise topographical maps is usually completed by the third postnatal week. Cytokines participate in the development and plasticity of the nervous system. We have previously shown that in vivo treatment with interleukin 2 disrupts the retinocollicular topographical order in early stages of development.

Nutritional tryptophan restriction and the role of serotonin in development and plasticity of central visual connections.

Tryptophan is an essential amino acid and metabolic precursor of serotonin. Serotonin is both a classical neurotransmitter and a signaling molecule that plays crucial roles in the development of neural circuits and plasticity. The specification of neural circuits in rodents occurs during the postnatal period with conspicuous influence of environmental factors including the nutritional status.

Neonatal tryptophan dietary restriction alters development of retinotectal projections in rats.

The specification of sensory neural circuits includes the elimination of transitory axon collaterals/synapses that takes place during early post natal life, an important step for the acquisition of topographical order of sensory systems. Serotonin has been implicated in the patterning of connections in subcortical and cortical circuits. We investigated the effects of the dietary restriction of the only serotonin precursor, tryptophan, on the development of the uncrossed retinotectal pathway in pigmented rats.

Matrix metalloproteinase-9 is involved in the development and plasticity of retinotectal projections in rats.

Objective: During postnatal development, retinotectal projections undergo a process of misplaced axon elimination, leading to a topographical matching between the retinal surface and the superior colliculus. Matrix metalloproteinases (MMPs) have been implicated in the development and plasticity of the nervous system. We studied the expression and role of MMPs during normal development of retinotectal projections and after monocular enucleation-induced plasticity.