Timed hypocaloric feeding and melatonin synchronize the suprachiasmatic clockwork in rats, but with opposite timing of behavioral output.

Temporal organization of the molecular clockwork and behavioral output were investigated in nocturnal rats housed in constant darkness and synchronized to nonphotic cues (daily normocaloric or hypocaloric feeding and melatonin infusion) or light (light-dark cycle and daily 1-h light exposure). Clock gene (Per1, Per2 and Bmal1) and clock-controlled gene (Vasopressin) expression in the suprachiasmatic nuclei was assessed over 24 h. Light and exogenous melatonin synchronized the molecular clock, signaling, respectively, 'daytime' and 'nighttime', without affecting temporal organization of behavioral output (rest/activity rhythm).

Quantification and localization of PEGylated polycyanoacrylate nanoparticles in brain and spinal cord during experimental allergic encephalomyelitis in the rat.

Under healthy conditions, the blood-brain barrier (BBB) limits the passage of solutes and cells from the blood to the CNS. During neurological diseases, BBB permeability increases dramatically and it has been hypothesized that drug carrier systems such as polymeric nanoparticles could cross the BBB and penetrate into the CNS. PEGylated polyalkylcyanoacrylate nanoparticles (long-circulating carrier) are one such system and have been investigated during experimental allergic encephalomyelitis (EAE).

Distribution of albumin nanoparticles in animals induced with the experimental allergic encephalomyelitis.

Experimental allergic encephalomyelitis (EAE) is an autoimmune disease characterised by a disruption of the blood-brain barrier (BBB), demyelination and a relevant inflammatory reaction with an intense infiltration of macrophages. These neurological disorders are similar to those observed in the multiple sclerosis (MS) disease. The use of different liposomes and adeno-associated virus has been proposed for improving the treatment of this pathogenesis.

Distribution in ocular structures and optic pathways of immunocompetent and glial cells in an experimental allergic encephalomyelitis (EAE) relapsing model.

Relapsing experimental allergic encephalomyelitis (EAE) was induced in DA rats and the ocular pathologic events were examined at the various phases of the illness. About 80% of EAE rats presented anterior uveitis (AU), even after complete EAE recovery. We studied the phenotype and localization of immunocompetent cells, the major histocompatibility complex (MHC) class I and II antigen expression, as well as the chemokine monocyte chemoattractant protein-1 (MCP-1) appearance.

Behavioural and glial changes in old rats following environmental enrichment.

The effects of enriched environment on short-term memory for event durations and on astrocytes (cell density, cell area and % of GFAP immunoreactivity) in hippocampus (Hi), frontal cortex (FC) and corpus callosum (CC) were analysed in old rats housed from weaning to the end of behavioural testing (23 months) either in standard (SC) or in enriched (EC) conditions and in young adults (5 months) all housed in SC. Old SC and EC and young SC rats trained (for 2 months) or not, in a Symbolic Delayed Matching to Sample Task, had to discriminate and remember two (2- and 10-s) signals after short retention intervals. Results confirm the aging-related acquisition and memory deficit.

Basic fibroblast growth factor (bFGF) injection activates the glial reaction in the injured adult rat brain.

Reactive gliosis is a reaction of glial cells to trauma which is characterized by a phenotypic modification of astrocytes, as well as by a proliferation and a migration of some of these cells to form a glial scar. This scar is currently considered as a physical impediment to neuronal regrowth but it may also be involved in wound healing since the astrocytes beside microglia play a phagocytic role in the clearance of post-traumatic debris. Growth factors are released in the area of the injury and at least some of them could be involved in gliosis.

Expression of the neuron-specific enolase gene by rat oligodendroglial cells during their differentiation.

We have examined the regulation of neuron-specific gamma-enolase gene (NSE) expression in oligodendrocytes at various steps of their differentiation/maturation. We have demonstrated for the first time that NSE is expressed in oligodendroglial cells in vitro and in vivo, and only at a certain stage of differentiation. A heterogeneity of the gamma subunit was observed in cultured oligodendrocytes and the same one was found in adult rat brain.

7 beta-hydroxycholesterol and 7 beta-hydroxycholesteryl-3-esters reduce the extent of reactive gliosis caused by an electrolytic lesion in rat brain.

Electrolytic lesions performed in brain cortex of six-day-old or adult rats resulted in the appearance of many reactive astrocytes around the injury site after a postoperative delay of eight days. They were revealed by immunohistochemistry using antibodies against glial fibrillary acidic protein. Injection of tritiated thymidine 24 h prior to autopsy indicated that, in neonates, 50% of the reactive astrocytes were proliferating.

Reactive astrogliosis after basic fibroblast growth factor (bFGF) injection in injured neonatal rat brain.

Reactive gliosis was revealed by immunocytochemistry using antibodies against the glial fibrillary acidic protein (GFAP) after a stab or an electrolytic lesion administered to the cerebral cortex, corpus callosum, striatum, or hippocampus of a 6-day-old rat. The intensity of the gliosis was about the same in the various structures injured and did not change with the delay of 3, 7, or 20 days between the injury and the sacrifice of the animals. When basic fibroblast growth factor (bFGF) was injected in the lesion locus just after the lesion was performed, it resulted (as soon as 3 days after injury) in a strong astrogliosis that was enhanced after a delay of 7 days, the astrocytes in the lesion area exhibiting enlarged cell processes and intense GFAP-positive immunoreactivity.

Primary cultures of astrocytes from different brain areas of newborn rats and effects of basic fibroblast growth factor.

The effects of basic fibroblast growth factor (bFGF) on the morphology and the expression of glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS) in cultured astrocytes prepared from various areas of newborn rat brain was studied. The brain was dissected in two ways, either the telencephalon (area A) and the diencephalon (area B) were dissected out of the brain (without olfactory bulbs, mesencephalon and cerebellum) or the brain was cut transversely into 3 parts (areas 1, 2 and 3). Area 1 (the anterior part) included the frontal cortex, the olfactory nuclei, the neostriatum, the accumbens nucleus and the septum; area 2 (the medial part) included the cortex, hippocampus, amygdale, thalamus and hypothalamus, and area 3 (the posterior part) included the occipital cortex, the posterior part of hippocampus and thalamus and the mamillary bodies.

Effects of basic fibroblast growth factor (bFGF) on choline acetyltransferase activity and astroglial reaction in adult rats after partial fimbria transection.

Adult rats received a partial and unilateral transection of the fimbria. They received then intracerebroventricular (i.c.

Prefrontal cortex aspiration in pups and juvenile rats: behavioural changes and recovery of function.

Male Wistar rats sustaining prefrontal cortex aspiration or sham operation at 6 days or 30 days of age were submitted to the following behavioural tests: open-field, acquisition and retention of two-way active as well as passive avoidance tasks. In the open-field the locomotor activity proved enhanced in all the aspirated animals and this enhancement lasted for 30 days. In the two-day active avoidance task, an acquisition deficit was observed in both aspirated groups; but when retrained one month later, they were able to acquire the avoidance task like sham-operated rats and no difference appeared between the groups aspirated at 6 or at 30 days of age.

Preoperative enrichment and behavioral recovery in rats with septal lesions.

To assess the behavioral effects of preoperative differential housing male rats were placed in either enriched or isolated environments at weaning prior to receiving either sham operations or septal lesions when 57 days of age. Rats with septal lesions showed reduced habituation of ambulation and initially made fewer rears in an empty open field but made more object-contacts coupled with a lack of habituation in the object-filled field. Septal rats also showed severe impairments when tested in a 12-arm radial maze with 7 arms baited and 5 arms unbaited.

Neonatal brain damage and recovery: intraventricular injection of NGF at time of injury alters performance of active avoidance.

Rats were given lesions of either the ventromedial hypothalamus (VMH) or septal nucleus at 7 days of age and then were tested repeatedly in an active avoidance task (A.A.) from 20 to 80 days.

Influence of rearing conditions on the acquisition of the two-way active avoidance responses by rats septalectomized at an early age.

When performed in the adult 3-month old rat, septal lesions facilitated the acquisition of a two-way active avoidance (AA) task as compared to animals sham-operated at the same age. When performed in the 7-day-old rat pup, the same lesion also clearly facilitated the 2-way AA acquisition by the rats when adult and, more especially so, when the rats were isolation-reared from weaning. The performances of these early-septal rats reared in isolation did not differ from those of rats septalectomized at adult age, while the performances of the early-septal rats that had been group-reared from weaning proved to be lower than that of adult-operated rats, with regard to both number of shocks avoided and mean response latencies in the initial phase of acquisition.