Search results for "Cortex"
showing 10 items of 1827 documents
A repetitive intracortical microstimulation pattern induces long-lasting synaptic depression in brain slices of the rat primary somatosensory cortex.
2000
Repetitive intracortical microstimulation (ICMS) applied to the rat primary somatosensory cortex (SI) in vivo was reported to induce reorganization of receptive fields and cortical maps. The present study was designed to exam- ine the effect of such an ICMS pattern applied to layer IV of brain slices containing SI on the efficacy of synaptic in- put to layer II/III. Effects of ICMS on the synaptic strength was quantified for the first synaptic component ( s1) of cor- tical field potentials (FPs) recorded from layer II/III of SI. FPs were evoked by stimulation in layer IV. The pattern of ICMS was identical to that used in vivo. However, stimula- tion intensity had to be raised to induce an a…
The superoxide anion is involved in the induction of long-term potentiation in the rat somatosensory cortex in vitro.
2004
Abstract The involvement of the superoxide anion (O2−) in the induction of neocortical long-term potentiation (LTP) was examined in rat brain slices containing the primary somatosensory cortex. Field potentials evoked by stimulation in cortical layer IV were recorded from layer II/III. In control experiments, tetanic high-frequency stimulation (HFS) resulted in essentially input-specific, NMDA receptor-dependent LTP (20.2±3.0% increase in field potential amplitude). When the availability of intracellular O2− was reduced by application of the cell membrane-permeable O2− scavengers MnTBAP or CP-H (spin trap), HFS-induced LTP was attenuated to 12.0±1.7% and 8.7±3.1% increase, respectively. In …
Role of the amygdala in antidepressant effects on hippocampal cell proliferation and survival and on depression-like behavior in the rat
2021
The stimulation of adult hippocampal neurogenesis by antidepressants has been associated with multiple molecular pathways, but the potential influence exerted by other brain areas has received much less attention. The basolateral complex of the amygdala (BLA), a region involved in anxiety and a site of action of antidepressants, has been implicated in both basal and stress-induced changes in neural plasticity in the dentate gyrus. We investigated here whether the BLA modulates the effects of the SSRI antidepressant fluoxetine on hippocampal cell proliferation and survival in relation to a behavioral index of depression-like behavior (forced swim test). We used a lesion approach targeting th…
Prognostic factors in stage III-IV adrenocortical carcinomas (ACC): an European Network for the Study of Adrenal Tumor (ENSAT) study
2015
Background: The clinical course of advanced adrenocortical carcinoma (ACC) is heterogeneous. Our study aimed primarily to refine and make headway in the prognostic stratification of advanced ACC.Patients and methods: Patients with advanced ENSAT ACC (stage III or stage IV) at diagnosis registered between 2000 and 2009 in the ENSAT database were enrolled. The primary end point was overall survival (OS). Parameters of potential prognostic relevance were selected. Univariate and multivariate analyses were carried out: model 1 'before surgery'; model 2 'post-surgery'.Results: Four hundred and forty-four patients with advanced ENSAT ACC (stage III: 210; stage IV: 234) were analyzed. After a medi…
l-[3H]lysine binding to rat retinal membrane: I. Quantitative determination and characterization of the binding sites
1986
A saturable reversible binding to membranes from rat retina has been found for L-[3H]lysine. Specific binding is time, temperature and protein concentration-dependent, and shows stereospecificity. The best computer fits of the experimental data are obtained with a receptor model based on two independent binding sites, of which only one site with a Kd value of 229.4 +/- 14.23 nM and a Bmax of 2.04 +/- 0.11 pmol/mg protein could be characterized satisfactorily. Several compounds included putative neurotransmitters have moderate or no affinity for L-lysine binding sites. A different pattern of distribution of L-[3H]lysine binding sites is observed among various regions of the brain, with the h…
Understanding Cannabinoid Psychoactivity with Mouse Genetic Models
2007
Marijuana and its main psychotropic ingredient Δ9-tetrahydrocannabinol (THC) exert a plethora of psychoactive effects through the activation of the neuronal cannabinoid receptor type 1 (CB1), which is expressed by different neuronal subpopulations in the central nervous system. The exact neuroanatomical substrates underlying each effect of THC are, however, not known. We tested locomotor, hypothermic, analgesic, and cataleptic effects of THC in conditional knockout mouse lines, which lack the expression of CB1 in different neuronal subpopulations, including principal brain neurons, GABAergic neurons (those that release γ aminobutyric acid), cortical glutamatergic neurons, and neurons expres…
Olfactory bulbectomy, but not odor conditioned aversion, induces the differentiation of immature neurons in the adult rat piriform cortex.
2011
International audience; The piriform cortex layer II of young-adult rats presents a population of prenatally generated cells, which express immature neuronal markers, such as the polysialylated form of the neural cell adhesion molecule (PSA-NCAM) or doublecortin (DCX), and display structural characteristics of immature neurons. The number of PSA-NCAM/DCX expressing cells in this region decreases markedly as age progresses, suggesting that these cells differentiate or die. Since the piriform cortex receives a major input from the olfactory bulb and participates in olfactory information processing, it is possible that the immature neurons in layer II are affected by manipulations of the olfac…
Prenatal exposure to the CB1 receptor agonist WIN 55,212-2 causes learning disruption associated with impaired cortical NMDA receptor function and em…
2005
The aim of this study was to investigate whether prenatal exposure to the cannabinoid CB1 receptor agonist WIN 55,212-2 (WIN) at a daily dose devoid of overt signs of toxicity and/or gross malformations (0.5 mg/kg, gestation days 5-20), influences cortical glutamatergic neurotransmission, learning and emotional reactivity in rat offspring. Basal and K+-evoked extracellular glutamate levels were significantly lower in cortical cell cultures obtained from pups exposed to WIN during gestation with respect to those measured in cultures obtained from neonates born from vehicle-treated dams. The addition of NMDA to cortical cell cultures from neonates born from vehicle-treated dams concentration-…
Putative role of nitric oxide synthase isoforms in the changes of nitric oxide concentration in rat brain cortex and cerebellum following sevoflurane…
2005
We have previously observed an increase in nitric oxide (NO) content in rat brain cortex following halothane, sevoflurane or isoflurane anaesthesia. This study was undertaken in order to determine whether isoform-specific nitric oxide synthase (NOS) inhibitors and inducers could modify these increases in NO contents. Rats were subjected to isoflurane and sevoflurane anaesthesia with concomitant administration of neuronal nitric oxide synthase (nNOS) inhibitor 7-Nitro-indazole (7-NI), inducible nitric oxide synthase (iNOS) inhibitor 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT) or lipopolysaccharide. NO concentration in different organs was measured by electron paramagnetic resonance (E…
Intermittent cortical stimulation evokes sensitization to cocaine and enduring changes in matrix and striosome neuron responsiveness
2005
Both the behavioral sensitization syndrome and the changes in the responsiveness of striatal neurons evoked by chronic cocaine exposure may be linked to enhanced neocortical activity, yet a direct demonstration of the effects of cortical stimulation on these parameters is lacking. We have found that repeated stimulation of the rat prelimbic cortex with picrotoxin (0.25 microg/0.25 microl, five injections on alternate days followed by 7-day withdrawal) contributed to increase c-Fos protein expression in the striosomes of the dorsolateral striatum, while producing the opposite effect in the matrix compartment, after a single exposure to cocaine (25 mg/kg). Moreover, rats exposed to cortical s…