Search results for " and ocular physiology"
showing 10 items of 237 documents
Molecular Histochemistry of Nicotinic Receptors in Human Brain
1997
Only a decade ago the existence and functional significance of central nervous nicotinic acetylcholine receptors (nAChR) was still a subject of controversy. Today, the importance of this receptor class for signal transduction in human brain in normal and pathological conditions has become quite evident. nAChRs have turned out to be important pharmacological targets in disorders like Alzheimer’s disease (AD) (Arneric et al., 1994). One prerequisite to understand nAChR function is a detailed study of the cellular distribution of nAChR subtypes. In recent years several human-specific data have been made available. This paper attempts to show actual developments in this field, summarizing the e…
Just noticeable differences in component concentrations modify the odor quality of a blending mixture.
2008
International audience; The odors we perceive are mainly the result of mixtures of odorants that, however, are commonly perceived as single undivided entities; nevertheless, the processes involved remain poorly explored. It has been recently reported that perceptual blending based on configural olfactory processing can cause odorant mixtures to give rise to an emergent odor not present in the components. The present study examined whether specific component proportions are required to elicit an emergent odor. Starting from the composition of a ternary target mixture in which an emergent pineapple odor was perceived, 4 concentration levels of each component were chosen to elicit just noticea…
Perceptual blending in odor mixtures depends on the nature of odorants and human olfactory expertise.
2012
International audience; Our olfactory system is confronted with complex mixtures of odorants, often recognized as single entities due to odor blending (e.g., coffee). In contrast, we are also able to discriminate odors from complex mixtures (e.g., off-odors). Therefore, the olfactory system is able to engage either configural or elemental processes when confronted with mixtures. However, the rules that govern the involvement of these processes during odor perception remain poorly understood. In our first experiment, we examined whether simple odorant mixtures (binary/ternary) could elicit configural perception. Twenty untrained subjects were asked to evaluate the odor typicality of mixtures…
Time-course evaluation of survival and treatment in FIRE-3 trial (AIO KRK0306).
2016
3528Background: To investigate overall survival (OS) differences in FIRE-3 in context of exposure to treatments (i.e. first-, second-, third-line) in time course. Methods: We compared OS in FIRE-3 ...
Phasic GABAA-receptor activation is required to suppress epileptiform activity in the CA3 region of the immature rat hippocampus
2012
Summary Purpose: Despite the consistent observation that γ-aminobutyric acid A (GABAA) receptors mediate excitatory responses at perinatal stages, the role of the GABAergic system in the generation of neonatal epileptiform activity remains controversial. Therefore, we analyzed whether tonic and phasic GABAergic transmission had differential effects on neuronal excitability during early development. Methods: We performed whole cell patch-clamp and field potential recordings in the CA3 region of hippocampal slices from immature (postnatal day 4–7) rats to analyze the effect of specific antagonists and modulators of tonic and phasic GABAergic components on neuronal excitability. Key Findings…
Amyloid Beta-Mediated Changes in Synaptic Function and Spine Number of Neocortical Neurons Depend on NMDA Receptors
2021
Onset and progression of Alzheimer’s disease (AD) pathophysiology differs between brain regions. The neocortex, for example, is a brain region that is affected very early during AD. NMDA receptors (NMDARs) are involved in mediating amyloid beta (Aβ) toxicity. NMDAR expression, on the other hand, can be affected by Aβ. We tested whether the high vulnerability of neocortical neurons for Aβ-toxicity may result from specific NMDAR expression profiles or from a particular regulation of NMDAR expression by Aβ. Electrophysiological analyses suggested that pyramidal cells of 6-months-old wildtype mice express mostly GluN1/GluN2A NMDARs. While synaptic NMDAR-mediated currents are unaltered in 5xFAD …
1-Methyl-?-carboline (Harmane), a potent endogenous inhibitor of benzodiazepine receptor binding
1980
The interaction of several beta-carbolines with specific [3H]-flunitrazepam binding to benzodiazepine receptors in rat brain membranes was investigated. Out of the investigated compounds, harmane and norharmane were the most potent inhibitors of specific [3H]-flunitrazepam binding, with IC50-values in the micromolar range. All other derivatives, including harmine, harmaline, and several tetrahydroderivatives were at least ten times less potent. Harmane has been previously found in rat brain and human urine, so it is the most potent endogenous inhibitor of specific [3H]-flunitrazepam binding known so far, with a several fold higher affinity for the benzodiazepine receptor than inosine and hy…
Sensory preconditioning in newborn rabbits: from common to distinct odor memories.
2013
Brief Communication; International audience; This study evaluated whether olfactory preconditioning is functional in newborn rabbits and based on joined or independent memory of odorants. First, after exposure to odorants A+B, the conditioning of A led to high responsiveness to odorant B. Second, responsiveness to B persisted after amnesia of A. Third, preconditioning was also functional with two overlapping pairs of odorants (A+B and B+C) and amnesia of one odorant did not affect memory of the others. Thus, incidental pairing of odorants allows reinforcement of one odorant to implicitly reinforce the others, the bond then vanishes, and the memory of each element becomes independent.
A family of heterometallic wheels containing potentially fourteen hundred siblings
2005
The synthesis and structure of new heterometallic wheels are reported, with preliminary studies of selected compounds.
Familial amyloidosis: great progress for an orphan disease.
2015
Familial amyloidosis: Great progress for an orphan disease Ana Paula Barreiros1,2,*, Gerd Otto3, Bita Kahlen1, Andreas Teufel1,2, Peter R. Galle1 1Department of Internal Medicine I, Universitatsmedizin of the Johannes Gutenberg-University Mainz, Germany; 2Department of Internal Medicine I, Universitatsklinikum of the University Regensburg, Germany; 3Department of Hepatobiliary and Transplantation Surgery, Universitatmedizin of the Johannes Gutenberg-University Mainz, Germany. *Corresponding author. Address: Universitatsklinikum Regensburg, Department of Internal Medicine I, Franz-Josef-Strauss Allee 11, 93053 Regensburg, Germany. Tel.: +49 941-944-7021. E-mail address: Ana.Barreiros@ukr.de …