Search results for "Transmission"

Glucose plus choline improve passive avoidance behaviour and increase hippocampal acetylcholine release in mice.

2001

The present study tests the effects of glucose and choline, the biosynthetic precursors of acetylcholine, on passive avoidance behaviour and hippocampal acetylcholine release measured by microdialysis in awake mice. Glucose (10 and 30mg/kg) or choline chloride (6-60mg/kg), given by i.p. injection immediately after training, dose-dependently enhanced retention in an inhibitory avoidance task. Combinations of low doses of glucose (10mg/kg) and choline chloride (20mg/kg) which alone were submaximally effective significantly increased retention latencies in a synergistic manner, an effect which was sensitive to atropine (0.5mg/kg). This beneficial effect vanished when higher doses of glucose or…

The pathological hallmarks of Alzheimer’s disease derive from compensatory responses to NMDA receptor insufficiency

2018

AbstractAlzheimer’s disease is characterized by intracellular aggregates of hyperphosphorylated tau protein and extracellular plaques of amyloid β peptide, a product of APP processing. The origin of these pathological hallmarks has remained elusive. Here, we have tested the idea that both alterations, at the onset of the disease, may constitute compensatory responses to the same causative and initial trigger, namely NMDA receptor insufficiency. Treatment of rat cortical neurons with the specific NMDA receptor antagonist AP5 within 4 h caused a significant increase in tau phosphorylation at the AT8 and S404 epitopes as well as an increase in APP expression and Aβ 40 secretion. Single intrape…

Study and modulation of human cortical excitability with transcranial magnetic stimulation.

1998

Transcranial magnetic stimulation (TMS) can be applied in different paradigms to obtain a measure of various aspects of cortical excitability. These different TMS paradigms provide information about different neurotransmitter systems, enhance our understanding about the pathophysiology of neuropsychiatric conditions, and in the future may be helpful as a guide for pharmacological interventions. In addition, repetitive TMS (rTMS) modulates cortical excitability beyond the duration of the rTMS trains themselves. Depending on rTMS parameters, a lasting inhibition or facilitation of cortical excitability can be induced. These effects can be demonstrated neurophysiologically or by combining rTMS…

Changes in glutamatergic neurotransmission within the migraine cycle

2013

Background Although some neurophysiological studies have showed cortical excitability changes during different phases of the migraine cycle, the pathophysiological mechanisms underlying attacks recurrence remain unknown. Here we evaluated the response of the migraine motor-cortex to brief trains of 5-Hz repetitive transcranial magnetic stimulation (rTMS) in order to study, indirectly, presynaptic mechanisms of glutamatergic neurotransmission across the different phases of the migraine cycle.

Beta-adrenoceptor stimulation enhances transmitter output from the rat phrenic nerve.

1988

Abstract 1. Neurally-evoked output of newly synthesized [3H]-acetylcholine from the rat phrenic nerve was measured in the absence of cholinesterase inhibitors. 2. Noradrenaline and isoprenaline enhanced neurally-evoked transmitter output markedly. Moreover, immediately after the application of noradrenaline the basal tritium efflux increased significantly. 3. Pretreatment with propranolol (0.1 mumol l-1) or atenolol (0.3 mumol l-1) completely prevented the stimulatory effect of noradrenaline and isoprenaline on evoked transmitter output. 4. The facilitatory effect of isoprenaline declined, when the exposure time was increased. This observation supports the assumption that beta-adrenoceptors…

Global change and human vulnerability to vector-borne diseases

2013

This e-book presents a collection of research and review articles related to the spread, control and basic understanding of vector borne diseases all over the world. It is well known that a multidisciplinary point of view is necessary in order to develop a global vision of this emergent problem. Therefore, in order to promote this holistic approach to the knowledge of vector borne diseases, this e-book contains a total of 19 collaborations of entomologists, epidemiologists, virologists, parasitologists, bacteriologists, zoologists and veterinarians of Europe, Africa, Asia, and America. The title perfectly reflects some of the global factors that are behind the emergence and/or reemergence o…

Broad beam transmission data for the shielding of brachytherapy facilities

2008

IRS-2 deficiency impairs NMDA receptor-dependent long-term potentiation

2011

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License.-- et al.

Epidemiological profile of patients infected by Human Immunodeficiency Virus (HIV)

2009

Introduction. The aim of the present work is to identify the principal characteristics of a sample of individuals at the moment of diagnosis of HIV infection. Material and methods. Descriptive, retrospective study, based on the hospital clinical records of 70 HIV+ patients, without AIDS, selected by means of simple aleatory sampling. Results. Transmission categories: Users of Injectable Drugs (UID) 81.4%, heterosexuals 10%, homo/bisexuals 4.3% and transfusions/plasma donors 2.9%, sex: ratio man/woman = 3.8/1, average age on diagnosis: 27.3 ± 7.0 years (UID 26.3 ± 5.1 years, heterosexuals 29.6 ± 2.1 years, homo/bisexuals 27.3 ± 3.9 and transfusions/plasma donors 51.4 ± 23.1 years (p = 0.02).…

Acetylcholine overflow during infusion of a high potassium-low sodium solution into the perfused chicken heart in the absence and presence of physost…

1977

1. The effect of infusion of a modified Tyrode's solution (“high K+-low Na+ solution”) into the isolated chicken heart on the content of acetylcholine in the tissue and the overflow of acetylcholine were compared to those evoked by vagal stimulation. 2. The release of acetylcholine was measured over 15-min periods of either stimulation of the vagus nerves (40 V, 1 ms) at 20 Hz or of infusion of the high K+-low Na+ solution (108 mM K+, 44 mM Na+). 3. Both stimuli caused a maximum overflow of acetylcholine in the first few minutes whether or not 10−6 M physostigmine was present. The overflow was maintained during the vagal stimulation at a constant rate of at least 35% the initial rate, where…