Reduction of GFAP induced by long dark rearing is not restricted to visual cortex

Corvetti, Luigi; Aztiria, Eugenio; Domenici, Luciano

doi:10.1016/j.brainres.2005.10.072

Cited by 13 publications

(9 citation statements)

References 25 publications

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“…2005; Bengoetxea et al 2008) and astroglial (Corvetti et al. 2003, 2006) components of the cortex (see reviews by Markham & Greenough, 2004; Spires & Hannan, 2005).…”

Section: Introductionmentioning

confidence: 99%

Physical exercise is required for environmental enrichment to offset the quantitative effects of dark‐rearing on the S‐100β astrocytic density in the rat visual cortex

2009

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After birth, exposure to visual inputs modulates cortical development, inducing numerous changes in all of the components of the visual cortex. Most of the cortical changes thus induced occur during what is called the critical period. Astrocytes play an important role in the development, maintenance and plasticity of the cortex as well as in the structure and function of the vascular network. Visual deprivation induces a decrease in the astroglial population, whereas enhanced experience increases it. Exposure to an enriched environment has been shown to prevent the effects of dark-rearing in the visual cortex. Our purpose was to study the effects of an enriched environment on the density of astrocytes per reference surface at the visual cortex of dark-reared rats, in order to determine if enhanced experience is able to compensate the quantitative effects of visual deprivation and the role of physical exercise on the enrichment paradigm. Pregnant Sprague-Dawley rats were raised in one of the following rearing conditions: control rats with standard housing (12-h light/dark cycle); in total darkness for the dark-rearing experiments; and dark-rearing in conditions of enriched environment without and with physical exercise. The astrocytic density was estimated by immunohistochemistry for S-100 β protein. Quantifications were performed in layer IV. The somatosensorial cortex barrel field was also studied as control. The volume of layer IV was stereologically calculated for each region, age and experimental condition. From the beginning of the critical period, astrocyte density was higher in control rats than in the enriched environment group without physical exercise, with densities of astrocytes around 20% higher at all of the different ages. In contrast, when the animals had access to voluntary exercise, densities were significantly higher than even the control rats. Our main result shows that strategies to apply environmental enrichment should always consider the incorporation of physical exercise, even for sensorial areas such as the visual area, where complex enriched experience by itself is not enough to compensate the effects of visual deprivation.

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“…2005; Bengoetxea et al 2008) and astroglial (Corvetti et al. 2003, 2006) components of the cortex (see reviews by Markham & Greenough, 2004; Spires & Hannan, 2005).…”

Section: Introductionmentioning

confidence: 99%

Physical exercise is required for environmental enrichment to offset the quantitative effects of dark‐rearing on the S‐100β astrocytic density in the rat visual cortex

2009

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“…Conversely, mice reared in constant dark conditions have a reduction in GFAP‐immunoreactive cells in the SCN . Comparable observations have been made in rats and hamsters . This suggests that astrocytes are regulated by changes in the light/dark cycle.…”

Section: Astrocytes and The Regulation Of Circadian Rhythmsmentioning

confidence: 85%

Astrocytes in neuroendocrine systems: An overview

Macdonald

Robb

Morrissey

et al. 2019

J Neuroendocrinology

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A class of glial cell, astrocytes, is highly abundant in the central nervous system (CNS). In addition to maintaining tissue homeostasis, astrocytes regulate neuronal communication and synaptic plasticity. There is an ever‐increasing appreciation that astrocytes are involved in the regulation of physiology and behaviour in normal and pathological states, including within neuroendocrine systems. Indeed, astrocytes are direct targets of hormone action in the CNS, via receptors expressed on their surface, and are also a source of regulatory neuropeptides, neurotransmitters and gliotransmitters. Furthermore, as part of the neurovascular unit, astrocytes can regulate hormone entry into the CNS. This review is intended to provide an overview of how astrocytes are impacted by and contribute to the regulation of a diverse range of neuroendocrine systems: energy homeostasis and metabolism, reproduction, fluid homeostasis, the stress response and circadian rhythms.

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“…Experience-dependent changes in evoked responses have also been reported in the hippocampus (Green et al, 1990;Moser, 1995;Gruart et al, 2006). Corvetti et al (2006) believe that besides the visual cortex, two other areas of the brain not directly involved in vision, the hippocampus CA1 area and the motor cortex were affected by light deprivation where lack of visual experience for long periods of time profoundly affects the phenotype of astrocytes. Taken together, it seems that visual signals influence the hippocampal circuits so that decreased sensory input leads to changes in neuronal activity, resulting in EPSPs with higher amplitude.…”

Section: Similar Effect Of Light Deprivation and Melatonin On The Evomentioning

confidence: 85%

Light deprivation improves melatonin related suppression of hippocampal plasticity

2009

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In early postnatal life, sensory inputs deeply influence development as well as function of the brain. Plasticity of synaptic transmission including its experimentally induced form, long-term potentiation (LTP), is affected by sensory deprivation in neocortex. This study is devoted to assess if dark rearing and a dark phase synthesized hormone melatonin influence LTP in the hippocampus, an area of brain involved in learning and memory. In vivo experiments were carried out on two groups of 45-days-old male Wistar rats kept in standard 12-h light/dark condition [light reared (LR) tested during the light phase] or in complete darkness [dark reared (DR)] since birth to testing. Each group, in turn, was divided to two, vehicle- and melatonin-treated, groups. Stimulating the Schaffer collaterals of CA3 area of hippocampus extracellular postsynaptic potentials (EPSPs) were recorded in the CA1 area. Having the stable baseline responses to the test pulses, the hippocampus was perfused by either vehicle or 2 microg melatonin and EPSPs were recorded for 30 min. Then, for induction of LTP, the tetanus was applied to the Schaffer collaterals and the field potentials were pooled for 120-min post-tetanus. The light deprivation resulted in a significant augmentation in the amplitude of baseline responses. Also, we observed a melatonin-induced increase in amplitude of the baseline recordings in either LR or DR animals. Tetanic stimulation elicited LTP of EPSPs in both LR and DR groups, robustly in the former where it lasted for about 90 min. Generally, melatonin inhibited the production of LTP in the two groups especially in the LR animals leading to a noticeable depression. We concluded that higher level of neuronal activity in the DR rats gives rise to a lower level of LTP. Weaker effect of melatonin on blocking the potentiation of post-tetanus EPSPs in the DR rats may be the result of a desensitization of melatonin receptors due to chronically increased levels of this hormone in the visually deprived rats.

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Reduction of GFAP induced by long dark rearing is not restricted to visual cortex

Cited by 13 publications

References 25 publications

Physical exercise is required for environmental enrichment to offset the quantitative effects of dark‐rearing on the S‐100β astrocytic density in the rat visual cortex

Physical exercise is required for environmental enrichment to offset the quantitative effects of dark‐rearing on the S‐100β astrocytic density in the rat visual cortex

Astrocytes in neuroendocrine systems: An overview

Light deprivation improves melatonin related suppression of hippocampal plasticity

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