Saumyendra N Sarkar

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L-type voltage-gated Ca(2+)channels (VGCC) play an important role in dendritic development, neuronal survival, and synaptic plasticity. Recent studies have demonstrated that the gonadal steroid estrogen rapidly induces Ca(2+) influx in hippocampal neurons, which is required for neuroprotection and potentiation of LTP. The mechanism by which estrogen rapidly(More)
Perturbations in dynamic properties of mitochondria including fission, fusion, and movement lead to disruption of energy supply to synapses contributing to neuropathology and cognitive dysfunction in Alzheimer׳s disease (AD). The molecular mechanisms underlying these defects are still unclear. Previously, we have shown that ERβ is localized in the(More)
Estrogens are potent neuroprotective hormones and mitochondria are the site of cellular life-death decisions. As such, it is not surprising that we and others have shown that estrogens have remarkable effects on mitochondrial function. Herein we provide evidence for a primary effect of estrogens on mitochondrial function, achieved in part by the import of(More)
Activated extracellular signal-regulated kinase (ERK) signaling mediated plasticity-related gene transcription has been proposed for one possible mechanism by which 17β-estradiol (E2) enhances synaptic plasticity and memory. Because activated ERK also enhances plasticity-related mRNA translation in the dendrites of neurons, we sought to determine the(More)
We recently demonstrated mitochondrial localization of estrogen receptor beta (ERbeta). We herein confirm the mitochondrial localization of ERbeta by the loss of mitochondrial ERbeta immunoreactivity in ERbeta knockdown cells. A phenotype change characterized as an increase in resistance to oxidative stressors is associated with ERbeta knockdown. ERbeta(More)
Neuromodulation of synaptic plasticity by 17β-estradiol (E2) is thought to influence information processing and storage in the cortex and hippocampus. Because E2 rapidly affects cortical memory and synaptic plasticity, we examined its effects on phosphorylation of calcium/calmodulin-dependent protein kinase II (CaMKII), extracellular signal-regulated kinase(More)
Estrogens exert neuroprotective activity in both in vivo and in vitro model systems. Herein, we report that both 17beta-estradiol and low concentrations of nitric oxide (NO) attenuate hydrogen peroxide (H2O2) induced toxicity in SK-N-SH cells, which express the neuronal nitric oxide synthase (nNOS). 17beta-estradiol rapidly induced an increase in NO levels.(More)
Presenilin (PS) in association with nicastrin (NICA) forms a gamma-secretase complex that plays a crucial role in facilitating intramembranous processing of Notch, a signaling receptor that is essential for neuronal fate specification and differentiation. Loss of function studies have implicated a role for PS1 in regulating neuronal differentiation in(More)
BACKGROUND Clozapine is the treatment of choice for medication refractory psychosis, but it does not benefit half of those put on it. There are numerous studies of potential post-clozapine strategies, but little data to guide the order of such treatment in this common clinical challenge. We describe a naturalistic observational study in 153 patients treated(More)
Aims and method In up to a quarter of patients, schizophrenia is resistant to standard treatments. We undertook a naturalistic study of 153 patients treated in the tertiary referral in-patient unit of the National Psychosis Service based at the Maudsley Hospital in London. A retrospective analysis of symptoms on admission and discharge was undertaken using(More)