Search results for "LONG-TERM POTENTIATION"

Metaplasticity of horizontal connections in the vicinity of focal laser lesions in rat visual cortex

2010

Focal cortical injuries are accompanied by a reorganization of the adjacent neuronal networks. An increased synaptic plasticity has been suggested to mediate, at least in part, this functional reorganization. Previous studies showed an increased long-term potentiation (LTP) at synapses formed by ascending fibres projecting onto layers 2/3 pyramidal cells following lesions in rat visual cortex. This could be important to establish new functional connections within a vertical cortical column. Importantly, horizontal intracortical connections constitute an optimal substrate to mediate the functional reorganization across different cortical columns. However, so far little is known about their p…

Individual differences in the induction of sensitisation or tolerance to the motor effects of morphine in mice

2001

Acute morphine administration produces hyperactivity in most strains of mice and some studies indicate that repeated treatment can induce a potentiation of this effect (sensitisation). With the object of determining whether the hyperactivity induced by morphine in OF1 mice shows sensitisation after repeated administration, we tested the effect of the pre-exposure to six daily injections of morphine on the subsequent hyperactivity induced by the same dose of this drug. Animals were treated with 40 mg/kg of morphine for seven days. After the last injection they were tested in an actimeter at different points at time (15, 30, 45 and 60 min). This repeated schedule of treatment produced sensiti…

Neurosteroids in the Retina

2003

Steroids may have a powerful role in neuronal degeneration. Recent research has revealed that steroids may influence the onset and progression of some retinal disorders as well as neurodegenerative diseases and, as in brain, they accumulate in the retina via a local synthesis (neurosteroids) and metabolism of blood-circulating steroid hormones. Their crucial role as neurodegenerative and neuroprotective agents has been also upheld in a retinal excitotoxic paradigm. These findings are reviewed especially from the emerging perspective that after an insult local changes in steroidogenic responses and consequent neurosteroid availability might turn out to be offensive or defensive cellular adap…

Serum Response Factor-Mediated Gene Regulation in a Drosophila Visual Working Memory

2013

Summary Background Navigation through the environment requires a working memory for the chosen target and path integration facilitating an approach when the target becomes temporarily hidden. We have previously shown that this visual orientation memory resides in the ellipsoid body, which is part of the central complex in the Drosophila brain. Former analysis of  foraging and ignorant mutants have revealed that a hierarchical PKG and RSKII kinase signaling cascade in a subset of the ellipsoid-body ring neurons is required for this type of working memory in flies. Results Here we show that mutants in the ellipsoid body open  ( ebo ) gene, which encodes the actin-binding protein Exportin 6, e…

ADIPOSE TISSUE-TARGETED STEM CELL TRANSPLANTATION FOR INSULIN RESISTANCE-RELATED CNS DEFICITS

Compelling evidence indicates that Type 2 Diabetes (T2D) and Alzheimer’s Disease (AD) may possibly share a common pathological origin, but the underlying mechanisms remain poorly understood. T2D is a known risk factor for AD and insulin resistance (hallmark of T2D) has been extensively documented in AD patients. Notably, insulin is important for learning and memory due to its role in LTP and LTD modulation. Adipose tissue (AT) dysfunction is a risk factor for T2D, in fact elevated levels of free fatty acids are prodromal to insulin resistance and have been reported in AD brains, as well. In this study, I used a mouse model (AtENPP1Tg mouse) that recapitulates typical characteristics of huma…

Long-Term Potentiation in Slices from Human Hippocampus

1988

Long-term potentiation (LTP) has been observed in slices from human hippocampi removed for intractable epilepsy using extra- and intracellular recording in vitro. Furthermore the effects of several neuroactive substances with possible relevance for synaptic plasticity was investigated. Human hippocampal neurones in vitro display properties very similar to the respective rodent cells.

FP187MITOCHONDRIAL DYSFUNCTION INDUCED BY TENOFOVIR IN RENAL CELLS. POTENTIATION OF THE EFFECTS BY CO-STIMULATION WITH ANGIOTENSIN II

2015

Long-Term Potentiation in the Neonatal Rat Barrel Cortex In Vivo

2012

Long-term potentiation (LTP) is important for the activity-dependent formation of early cortical circuits. In the neonatal rodent barrel cortex, LTP has been studied only in vitro . We combined voltage-sensitive dye imaging with extracellular multielectrode recordings to study whisker stimulation-induced LTP in the whisker-to-barrel cortex pathway of the neonatal rat barrel cortex in vivo . Single whisker stimulation at 2 Hz for 10 min induced an age-dependent expression of LTP in postnatal day (P) 0 to P14 rats, with the strongest expression of LTP at P3–P5. The magnitude of LTP was largest in the activated barrel-related column, smaller in the surrounding septal region, and no LTP could b…

Extremely Low Frequency Magnetic Fields Do Not Affect LTP-Like Plasticity in Healthy Humans.

2020

Introduction: Several studies explored, in vitro, the biological effects of extremely low-frequency magnetic fields (ELF-MFs) and reported the induction of functional changes in neuronal activity. In particular, ELF-MFs can influence synaptic plasticity both in-vitro and in animal models. Indeed, some studies reported an increase in long-term potentiation (LTP) whereas others suggested its reduction. However, no specific study has investigated such effect in humans. Aims: To evaluate whether ELF-MFs affect the propensity of the human cortex to undergo LTP-like plasticity. Methods: We designed a randomized, single-blind, sham-controlled, cross-over study on 10 healthy subjects. Cortical plas…

Hsp60 Protects against Amyloid β Oligomer Synaptic Toxicity via Modification of Toxic Oligomer Conformation

2019

Alzheimer's disease (AD) is the leading cause of dementia worldwide. While the etiology of AD remains uncertain, neurotoxic effects of amyloid beta oligomers (Aβo) on synaptic function, a well-established early event in AD, is an attractive area for the development of novel strategies to modify or cease the disease's progression. In this work, we tested the protective action of the mitochondrial chaperone Hsp60 against Aβo neurotoxicity, by determining the direct effect of Hsp60 in changing Aβo toxic conformations and thus reducing their dysfunctional synaptic binding and consequent suppression of long-term potentiation. Our data suggest that Hsp60 has a direct impact on Aβo, resulting in a…