scholarly journals Chronic Low Dose Neutron Exposure Results in Altered Neurotransmission Properties of the Hippocampus-Prefrontal Cortex Axis in Both Mice and Rats

2021 ◽  
Vol 22 (7) ◽  
pp. 3668
Author(s):  
Balaji Krishnan ◽  
Chandramouli Natarajan ◽  
Krystyn Z. Bourne ◽  
Leila Alikhani ◽  
Juan Wang ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Synaptic Plasticity ◽  
Low Dose ◽  
Synaptic Membrane ◽  
Synaptic Loss ◽  
Neurocognitive Impairments ◽  
Deep Space Exploration ◽  
Neutron Exposure ◽  
Mixed Field ◽  
First Time

The proposed deep space exploration to the moon and later to Mars will result in astronauts receiving significant chronic exposures to space radiation (SR). SR exposure results in multiple neurocognitive impairments. Recently, our cross-species (mouse/rat) studies reported impaired associative memory formation in both species following a chronic 6-month low dose exposure to a mixed field of neutrons (1 mGy/day for a total dose pf 18 cGy). In the present study, we report neutron exposure induced synaptic plasticity in the medial prefrontal cortex, accompanied by microglial activation and significant synaptic loss in the hippocampus. In a parallel study, neutron exposure was also found to alter fluorescence assisted single synaptosome LTP (FASS-LTP) in the hippocampus of rats, that may be related to a reduced ability to insert AMPAR into the post-synaptic membrane, which may arise from increased phosphorylation of the serine 845 residue of the GluA1 subunit. Thus, we demonstrate for the first time, that low dose chronic neutron irradiation impacts homeostatic synaptic plasticity in the hippocampal-cortical circuit in two rodent species, and that the ability to successfully encode associative recognition memory is a dynamic, multicircuit process, possibly involving compensatory changes in AMPAR density on the synaptic surface.

scholarly journals Methylglyoxal modification of TrkB promotes synaptic plasticity and enhances resilience to chronic stress

2018 ◽  
Author(s):  
Ziyin Wu ◽  
Yingxue Fu ◽  
Yinfeng Yang ◽  
Chao Huang ◽  
Chunli Zheng ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Synaptic Plasticity ◽  
Chronic Stress ◽  
Low Dose ◽  
Anxiety And Depression ◽  
Antidepressant Effects ◽  
Subsequent Activation

AbstractThe endogenous metabolite methylglyoxal (MGO) has recently emerged as a potential mediator of psychiatric disorders, such as anxiety and depression, but its precise mechanism of action remains poorly understood. Here, we find that MGO concentrations are decreased in the prefrontal cortex and hippocampus in rats subjected to chronic stress, and low-dose MGO treatment remarkedly enhances resilience to stress and alleviates depression-like symptoms. This effect is achieved by MGO’s promotion on the synaptic plasticity in prefrontal cortex and hippocampus. Both in vitro and in vivo experiments show that MGO provokes the dimerization and autophosphorylation of TrkB and the subsequent activation of downstream Akt/CREB signaling, which leads to a rapid and sustained expression of brain-derived neurotrophic factor (BDNF). We further demonstrate that MGO directly binds to the extracellular domain of TrkB, but not its intracellular domain. In addition, we also identify a natural product luteolin and its derivative lutD as potent inhibitors of Glyoxalase 1 and validate their antidepressant effects in chronic stress rat models. The antidepressant role of endogenous MGO provides a new basis for the understanding and therapeutic intervention design for stress-associated mental disorders.

HAEMOSTATIC CHANGES INDUCED BY TWO LOW DOSE TRIPHASIC ORAL CONTRACEPTIVES

1987 ◽  
Author(s):  
S J Machin ◽  
I J Mackie ◽  
K Walshe ◽  
M D Gillmer
Keyword(s):  
Oral Contraceptives ◽  
Protein C ◽  
Low Dose ◽  
Factor Vii ◽  
Cycle Period ◽  
Factor Xii ◽  
Factor X ◽  
Combined Oral Contraceptives ◽  
First Time ◽  
Protein C Activity

The haemostatic system was investigated in 26 women taking cyclically administered triphasic combined oral contraceptives for the first time during their first six cycles. Fourteen women received Logynon (mean dose 32.4μg ethinyloestradiol, 92pg progestagen) and 12 received SHD 415G (Schering) which contains a mean dosage of 32.4μg ethinyloestradiol and 78pg gestodene, a recently developed progesterone. The Logynon group showed a significant increase (p<0.005) in fibrinogen (pre-mean 284.4 g/1; after 1 cycle 347.3 g/1, after 6 cycles 318.6 g/1) , factor VII (65.8 u/1 to 73.9 u/1 to 83.2 u/1), factor XII (1.74 u/1 to 2.41 u/1, to 2.25 u/1), plasminogen (100.9 u/1 to 135.1 u/1 to 126.3 u/1); decrease in ATIII (115.9 u/1 to 103.1 u/1 to 93.4 u/1) but no significant change in factor X (98.4 u/1 to 108.9 u/1 to 102.4) or protein C (0.85 u/1 to 0.88 u/1 to 0.94 u/1) activity. The SHD 415G group showed similar changes with an increase in fibrinogen (247.9 g/1 to 330.8 g/1 to 373 .1 g/1), factor VII (63.1 u/1 to 73.1 u/1 to 90.3 u/1, factor X (98.3 u/1 to 112.0 u/1 to 124.4 u/1), factor XII (1.46 u/1, to 1.93 u/1, to 2.03 u/1), plasminogen (110.8 u/1 to 125.4 u/1 to 136.7 u/1); decrease in ATIII (113.1 u/1 to 96.3 u/1 to 89.7 u/1), but no change in protein C (0.84 u/1 to - 0.78 u/1 to 0.85 u/1) activity. These changes were apparent after the first cycle of therapy and the differences were maintained over the six cycle period. There was no increase in protein C activity despite changes in the other vitamin K dependent proteins factors VII and X. Both low oestrogen dose triphasic pills caused similar prothrombotic changes which were not modified by the new progesterone, gestodene.

scholarly journals Reductions in prefrontal activation predict off-topic utterances during speech production

2018 ◽  
Author(s):  
Paul Hoffman
Keyword(s):  
Prefrontal Cortex ◽  
Speech Production ◽  
Formal Analysis ◽  
Neural Systems ◽  
Healthy Older Adults ◽  
Linguistic Analyses ◽  
Complex Goal ◽  
First Time ◽  
Increased Activity ◽  
Selection Of

AbstractThe ability to speak coherently is essential for effective communication but declines with age: older people more frequently produce tangential, off-topic speech. Little is known, however, about the neural systems that support coherence in speech production. Here, fMRI was used to investigate extended speech production in healthy older adults. Computational linguistic analyses were used to quantify the coherence of utterances produced in the scanner, allowing identification of the neural correlates of coherence for the first time. Highly coherent speech production was associated with increased activity in bilateral inferior prefrontal cortex (BA45), an area implicated in selection of task-relevant knowledge from semantic memory, and in bilateral rostrolateral prefrontal cortex (BA10), implicated more generally in planning of complex goal-directed behaviours. These findings demonstrate that neural activity during spontaneous speech production can be predicted from formal analysis of speech content, and that multiple prefrontal systems contribute to coherence in speech.

First time, low dose citalopram use-related serotonin syndrome

2007 ◽  
Vol 28 (6) ◽  
pp. 1272-1274 ◽  
Author(s):  
S TUREDI ◽  
I ERAYDIN ◽  
A GUNDUZ ◽  
A KALKAN ◽  
U HOS
Keyword(s):  
Serotonin Syndrome ◽  
Low Dose ◽  
First Time

scholarly journals Synapse Plasticity in Motor, Sensory, and Limbo-Prefrontal Cortex Areas as Measured by Degrading Axon Terminals in an Environment Model of Gerbils (Meriones unguiculatus)

2009 ◽  
Vol 2009 ◽  
pp. 1-14 ◽  
Author(s):  
Janina Neufeld ◽  
Gertraud Teuchert-Noodt ◽  
Keren Grafen ◽  
York Winter ◽  
A. Veronica Witte
Keyword(s):  
Prefrontal Cortex ◽  
Synaptic Plasticity ◽  
Meriones Unguiculatus ◽  
Secondary Lysosome ◽  
Axon Terminals ◽  
Environment Model ◽  
Naturally Occurring ◽  
Synapse Plasticity ◽  
Map Adaptation ◽  
Cortical Map

Still little is known about naturally occurring synaptogenesis in the adult neocortex and related impacts of epigenetic influences. We therefore investigated (pre)synaptic plasticity in various cortices of adult rodents, visualized by secondary lysosome accumulations (LA) in remodeling axon terminals. Twenty-two male gerbils from either enriched (ER) or impoverished rearing (IR) were used for quantification of silver-stained LA. ER-animals showed rather low LA densities in most primary fields, whereas barrel and secondary/associative cortices exhibited higher densities and layer-specific differences. In IR-animals, these differences were evened out or even inverted. Basic plastic capacities might be linked with remodeling of local intrinsic circuits in the context of cortical map adaptation in both IR- and ER-animals. Frequently described disturbances due to IR in multiple corticocortical and extracortical afferent systems, including the mesocortical dopamine projection, might have led to maladaptations in the plastic capacities of prefronto-limbic areas, as indicated by different LA densities in IR- compared with ER-animals.

scholarly journals SUN-042 Low Dose Cyproterone Acetate for the Treatment of Transgender Women - a Retrospective Study

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Naomi Even-Zohar ◽  
Yael Sofer ◽  
Iris Yaish ◽  
Merav Serebro ◽  
Karen Tordjman ◽  
...  
Keyword(s):  
Cyproterone Acetate ◽  
Dose Group ◽  
Low Dose ◽  
Dose Range ◽  
Hormonal Treatment ◽  
Transgender Women ◽  
High Dose ◽  
Historical Cohort ◽  
Treatment Groups ◽  
First Time

Abstract Introduction : Transgender women with intact gonads receive lifelong hormonal treatment in order to suppress physiologic androgen production. Cyproterone acetate (CA) is the most comon antiandrogenic drug prescribed for this indication in Europe, with a dose range between 25-100 mg/day. Aim: To assess the effectiveness and safety of low dose (&lt;20 mg/day), compared with high dose (&gt;50 mg/day) CA treatment. Methods: Historical cohort study of transgender women treated in our department between January 2000 and October 2018. Results: There were 42 transgender women in the low dose group (LDG) and 32 in the high dose group (HDG). Age (27.9 ± 1.6 vs.28.9 ± 1.7 years) and follow up time (16.2 ± 2.2 vs. 20.1 ± 2.1 months) were similar in the LDG and HDG, respectively. At the last available visit, testosterone levels were effectively and similarly suppressed in both treatment groups (0.6 ± 0.1 vs 0.8 ± 0.3 nmol/l; p=0.37, for LDG and HDG respectively). Prolactin (659 ± 64 vs 486 ± 42 mIU/ml, p=0.02), LDL cholesterol (96.1 ± 5 vs 78.5 ± 4 mg/dl, p= 0.02) and triglycerides (93.3 ± 9 vs 69 ± 5 mg/dl; p=0.02) were higher in the HDG compared with LDG respectively. Side effects were common in the HDG (four cases of increased liver enzymes, one case of pulmonary embolism and one case of sudden death). Conclusion: We show for the first time that anti-androgenic treatment of transgender women with low dose CA is as effective as high dose treatment, but safer. We suggest incorporation of this observation in future guidelines.

Mixed receptors of AMPA and NMDA emulated using a ‘Polka Dot’-structured two-dimensional conjugated polymer-based artificial synapse

2020 ◽  
Vol 5 (9) ◽  
pp. 1324-1331
Author(s):  
Hong Han ◽  
Feng Ge ◽  
Mingxue Ma ◽  
Haiyang Yu ◽  
Huanhuan Wei ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Conjugated Polymer ◽  
Synaptic Membrane ◽  
Two Dimensional ◽  
Artificial Synapse

‘Polka dot’-structured two-dimensional conjugated polymer-based synaptic transistors successfully emulate different receptors on post-synaptic membrane and advanced forms of synaptic plasticity.

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