Search results for "PPO"

2018

Summary Directed transport of transmembrane proteins is generally believed to occur via intracellular transport vesicles. However, using single-particle tracking in rat hippocampal neurons with a pH-sensitive quantum dot probe that specifically reports surface movement of receptors, we have identified a subpopulation of neuronal EphB2 receptors that exhibit directed motion between synapses within the plasma membrane itself. This receptor movement occurs independently of the cytoskeleton but is dependent on cholesterol and is regulated by neuronal activity.

2016

During hippocampal sharp wave/ripple (SWR) events, previously occurring, sensory input-driven neuronal firing patterns are replayed. Such replay is thought to be important for plasticity-related processes and consolidation of memory traces. It has previously been shown that the electrical stimulation-induced disruption of SWR events interferes with learning in rodents in different experimental paradigms. On the other hand, the cognitive map theory posits that the plastic changes of the firing of hippocampal place cells constitute the electrophysiological counterpart of the spatial learning, observable at the behavioral level. Therefore, we tested whether intact SWR events occurring during t…

Genetic associations at 53 loci highlight cell types and biological pathways relevant for kidney function

2016

Reduced glomerular filtration rate defines chronic kidney disease and is associated with cardiovascular and all-cause mortality. We conducted a meta-analysis of genome-wide association studies for estimated glomerular filtration rate (eGFR), combining data across 133,413 individuals with replication in up to 42,166 individuals. We identify 24 new and confirm 29 previously identified loci. Of these 53 loci, 19 associate with eGFR among individuals with diabetes. Using bioinformatics, we show that identified genes at eGFR loci are enriched for expression in kidney tissues and in pathways relevant for kidney development and transmembrane transporter activity, kidney structure, and regulation o…

Critical re-evaluation of neuroglobin expression reveals conserved patterns among mammals.

2016

Neuroglobin (Ngb) is a respiratory protein that is almost exclusively expressed in the vertebrate nervous system. Despite many years of research, the exact function and even the expression sites of Ngb are still a matter of debate. However, to investigate hypotheses surrounding the potential roles of Ngb, a detailed knowledge of its major and minor expression sites is indispensable. We have therefore evaluated Ngb expression by extensive bioinformatic analysis using publicly available transcriptome data (RNA-Seq). During mammalian brain development, we observed low embryonic expression of Ngb mRNA and an increase after birth, arguing against a role of Ngb in fetal hypoxia tolerance. In adul…

LPA1, LPA2, LPA4, and LPA6receptor expression during mouse brain development

2019

Background:LPA is a small bioactive phospholipid that acts as an extracellularsignaling molecule and is involved in cellular processes, including cell prolifera-tion, migration, and differentiation. LPA acts by binding and activating at least sixknown G protein–coupled receptors: LPA1–6. In recent years, LPA has beensuggested to play an important role both in normal neuronal development andunder pathological conditions in the nervous system. Results:We show the expression pattern of LPA receptors during mouse braindevelopment by using qRT-PCR, in situ hybridization, and immunocytochemistry.Only LPA1,LPA2,LPA4,and LPA6 mRNA transcripts were detected throughoutdevelopment stages from embryoni…

Semaphorins in Adult Nervous System Plasticity and Disease

2021

Semaphorins, originally discovered as guidance cues for developing axons, are involved in many processes that shape the nervous system during development, from neuronal proliferation and migration to neuritogenesis and synapse formation. Interestingly, the expression of many Semaphorins persists after development. For instance, Semaphorin 3A is a component of perineuronal nets, the extracellular matrix structures enwrapping certain types of neurons in the adult CNS, which contribute to the closure of the critical period for plasticity. Semaphorin 3G and 4C play a crucial role in the control of adult hippocampal connectivity and memory processes, and Semaphorin 5A and 7A regulate adult neuro…

Allopregnanolone augments epileptiform activity of an in-vitro mouse hippocampal preparation in the first postnatal week.

2019

Abstract In the immature brain the neurotransmitter γ-amino butyric acid (GABA) mediates a membrane depolarization and can contribute to both, inhibition and excitation. Therefore the consequences of a positive modulation of GABA(A) receptors by neurosteroids on epileptiform activity are hard to predict. In order to analyze whether neurosteroids attenuate or exaggerate epileptiform activity in the immature brain, we investigated the effect of the neurosteroid allopregnanolone on epileptiform activity in an in-toto hippocampus preparation of early postnatal mice (postnatal days 4–7) using field potential recordings. These in-vitro experiments revealed that 0.5 μmol/L allopregnanolone had no …

New functions of Semaphorin 3E and its receptor PlexinD1 during developing and adult hippocampal formation

2018

AbstractThe development and maturation of cortical circuits relies on the coordinated actions of long and short range axonal guidance cues. In this regard, the class 3 semaphorins and their receptors have been seen to be involved in the development and maturation of the hippocampal connections. However, although the role of most of their family members have been described, very few data about the participation of Semaphorin 3E (Sema3E) and its receptor PlexinD1 during the development and maturation of the entorhino-hippocampal (EH) connection are available. In the present study, we focused on determining their roles both during development and in adulthood. We determined a relevant role for…

NO Hemodynamic Speed Limit for Hippocampal Neurogenesis

2019

Newborn dentate granule cells (DGCs) are continuously generated in the adult brain. The mechanism underlying how the adult brain governs hippocampal neurogenesis remains poorly understood. In this study, we investigated how coupling of pre-existing neurons to the cerebrovascular system regulates hippocampal neurogenesis. Using a new in vivo imaging method in freely moving mice, we found that hippocampus-engaged behaviors, such as exploration in a novel environment, rapidly increased microvascular blood flow velocity in the dentate gyrus. Importantly, blocking this exploration-elevated blood flow dampened experience-induced hippocampal neurogenesis. By imaging the neurovascular niche in comb…

Auxiliary α2δ1 and α2δ3 Subunits of Calcium Channels Drive Excitatory and Inhibitory Neuronal Network Development

2020

VGCCs are multisubunit complexes that play a crucial role in neuronal signaling. Auxiliary α2δ subunits of VGCCs modulate trafficking and biophysical properties of the pore-forming α1 subunit and trigger excitatory synaptogenesis. Alterations in the expression level of α2δ subunits were implicated in several syndromes and diseases, including chronic neuropathic pain, autism, and epilepsy. However, the contribution of distinct α2δ subunits to excitatory/inhibitory imbalance and aberrant network connectivity characteristic for these pathologic conditions remains unclear. Here, we show that α2δ1 overexpression enhances spontaneous neuronal network activity in developing and mature cultures of …