Streptozotocin diabetic mice display depressive-like behavior and alterations in the structure, neurotransmission and plasticity of medial prefrontal cortex interneurons.
Diabetes mellitus patients are at increased risk of developing depression, although the neurobiological bases of this comorbidity are not yet fully understood. These patients show CNS alterations, similar to those found in major depression, including changes in the structure and neurotransmission of excitatory neurons. However, although depressive patients and animal models also display alterations in inhibitory networks, little is known about the effects of diabetes on interneurons. Our main objective was to study the impact of diabetes on interneurons of the medial prefrontal cortex (mPFC), one of the regions most affected by major depression. For this purpose we have induced diabetes wit…
Effects of Aging on the Structure and Expression of NMDA Receptors of Somatostatin Expressing Neurons in the Mouse Hippocampus
Changes in the physiology, neurochemistry and structure of neurons, particularly of their dendritic spines, are thought to be crucial players in age-related cognitive decline. One of the most studied brain structures affected by aging is the hippocampus, known to be involved in different essential cognitive processes. While the aging-associated quantitative changes in dendritic spines of hippocampal pyramidal cells have already been studied, the relationship between aging and the structural dynamics of hippocampal interneurons remains relatively unknown. Spines are not a frequent feature in cortical inhibitory neurons, but these postsynaptic structures are abundant in a subpopulation of som…
Long term effects of peripubertal stress on excitatory and inhibitory circuits in the prefrontal cortex of male and female mice.
Abstract The impact of stressful events is especially important during early life, because certain cortical regions, especially the prefrontal cortex (PFC), are still developing. Consequently, aversive experiences that occur during the peripubertal period can cause long-term alterations in neural connectivity, physiology and related behaviors. Although sex influences the stress response and women are more likely to develop stress-related psychiatric disorders, knowledge about the effects of stress on females is still limited. In order to analyze the long-term effects of peripubertal stress (PPS) on the excitatory and inhibitory circuitry of the adult PFC, and whether these effects are sex-d…
Functional Integration of Neuronal Precursors in the Adult Murine Piriform Cortex
Abstract The extent of functional maturation and integration of nonproliferative neuronal precursors, becoming neurons in the adult murine piriform cortex, is largely unexplored. We thus questioned whether precursors eventually become equivalent to neighboring principal neurons or whether they represent a novel functional network element. Adult brain neuronal precursors and immature neurons (complex cells) were labeled in transgenic mice (DCX-DsRed and DCX-CreERT2 /flox-EGFP), and their cell fate was characterized with patch clamp experiments and morphometric analysis of axon initial segments. Young (DCX+) complex cells in the piriform cortex of 2- to 4-month-old mice received sparse synapt…
Effects of Dopamine on the Immature Neurons of the Adult Rat Piriform Cortex
The layer II of the adult piriform cortex (PCX) contains a numerous population of immature neurons. Interestingly, in both mice and rats, most, if not all, these cells have an embryonic origin. Moreover, recent studies from our laboratory have shown that they progressively mature into typical excitatory neurons of the PCX layer II. Therefore, the adult PCX is considered a “non-canonical” neurogenic niche. These immature neurons express the polysialylated form of the neural cell adhesion molecule (PSA-NCAM), a molecule critical for different neurodevelopmental processes. Dopamine (DA) is a relevant neurotransmitter in the adult CNS, which also plays important roles in neural development and …
Continuous neuronal integration in the cerebral cortex of rodents and humans
La plasticidad neuronal es la capacidad del sistema nervioso para realizar cambios funcionales adaptativos, durante el desarrollo y la edad adulta. Se refiere a todo tipo de cambios que modifican la forma y estructura de las neuronas y de las células gliales del sistema nervioso central (SNC). Entre los diferentes niveles de plasticidad que ocurren en el cerebro adulto, la neurogénesis es un tipo de plasticidad cerebral, que implica la producción e incorporación continua de nuevas neuronas en las redes neuronales funcionales. En el cerebro de los mamíferos adultos, las nuevas neuronas se generan tradicionalmente en dos "nichos neurogénicos canónicos": la zona subventricular (SVZ) y la zona …
PSA Depletion Induces the Differentiation of Immature Neurons in the Piriform Cortex of Adult Mice
Immature neurons are maintained in cortical regions of the adult mammalian brain. In rodents, many of these immature neurons can be identified in the piriform cortex based on their high expression of early neuronal markers, such as doublecortin (DCX) and the polysialylated form of the neural cell adhesion molecule (PSA-NCAM). This molecule plays critical roles in different neurodevelopmental events. Taking advantage of a DCX-CreERT2/Flox-EGFP reporter mice, we investigated the impact of targeted PSA enzymatic depletion in the piriform cortex on the fate of immature neurons. We report here that the removal of PSA accelerated the final development of immature neurons. This was revealed by a h…