Presenilin mutations are the main cause of familial Alzheimer's disease (FAD). Presenilins also play a key role in Ca 2+ homeostasis, and their FAD-linked mutants affect cellular handling several ways. We previously have demonstrated that presenilin 2 (PS2) decrease content endoplasmic reticulum (ER) by inhibiting sarcoendoplasmic -ATPase (SERCA) activity increasing ER leak. Here we focus on effect presenilins mitochondrial dynamics. By using genetically encoded indicators specifically...

Calcium influx in electrically non-excitable cells is regulated by the filling state of intracellular calcium stores. Depletion stores activates plasma membrane channels that are voltage-independent and highly selective for Ca2+ ions. We report here activation currents induced depletion requires a diffusible cytosolic factor washes out with time when dialyzing whole-cell configuration patch-clamp technique. The release-activated current (ICRAC) ionomycin- or inositol...

ICRAC (the best characterized Ca2+ current activated by store depletion) was monitored concurrently for the first time with [Ca2+] changes in internal stores. To establish quantitative and kinetic relationship between these two parameters, we have developed a novel means to clamp within stores of intact cells at any level. The advantage this approach, which is based on membrane-permeant low-affinity chelator N,N,N',N'-tetrakis (2-pyridylmethyl)ethylene diamine (TPEN), that ER can be lowered...

=ZOOp M of Ca2+/liter cell water (< 30% total exchangeable Ca2+) and takes up Ca2+ from the cytosol via a Ca2+-ATPase, blocked by thapsigargin.A second pool, ~4 0 bM/liter, is insensitive to both inositol 1,4,5trisphosphate, caffeine, thapsigargin released ionophore ionomycin.This pool probably heterogeneous its intracellular localization physiological roles remain undefined.The third ~1 7 Mmoles Ca2+/liter, was discharged combination ionomycin together with substance that collapsed pH...

Whole-cell patch-clamp recordings of membrane currents and Fura-2 measurements free intracellular calcium concentration ([Ca2+]i) were used to study influx through receptor-activated cation channels in rat peritoneal mast cells. Cation activated by the secretagogue compound 48/80, whereas a possible concomitant Ca2+ entry pathways depletion stores was blocked dialyzing cells with heparin. Heparin effectively suppressed transient release induced 48/80 abrogated inositol...

The neuroblastoma-like cell line N2A and the pheochromocytoma-like PC12 excrete about 20-25% of intracellular fluorescent Ca2+ indicator fura-2 during 10 min incubation at 37 degrees C. drug probenecid, known to inhibit membrane systems for transport organic anions [Cunningham, Israili & Dayton (1981) Clin. Pharmacol. 6, 135-151], inhibited excretion in both types. However, probenecid also had untoward effects on homeostasis cells. We therefore tested sulphinpyrazone, another inhibitor...

Abstract Accumulation of inositol phosphates (Ins-Ps, revealed by high performance liquid chromatography), changes the cytosolic free Ca2+ [( Ca2+]i, fura-2), membrane potential and ionic currents (revealed bis-oxonol patch clamping) were investigated in PC12 cells treated with bradykinin (BK). The phenomena observed (a) due to activation a B2 receptor (inhibitor studies) (b) unaffected pertussis toxin, cAMP analogs, inhibitors either cyclooxygenase or voltage-gated channels. During initial...

Receptor-activated Ca2+ influx was investigated in PC12 cells clones loaded with fura-2.Cells were stimulated a Ca2+-free medium and studied after reintroduction of the cation or addition Mn2+ into medium.A first component, independent receptor activation sustained by depletion intracellular inositol lY4,5-trisphosphate sensitive store (store-dependent influx, SDCI), identified experiments carbachol followed atropine agents that induce discharge without polyphosphoinositide hydrolysis:...

Release of Ca2+ from intracellular stores was studied in the parent PC12 cell line and recently isolated clones sensitive or insensitive to caffeine. In caffeine-sensitive cells cytosolic free concentration ([Ca2+]i) responses by xanthine drug stimulants receptors coupled inositol 1,4,5-trisphosphate (Ins-P3) generation (bradykinin, ATP) depend on separate pathways because 1) caffeine does not stimulate hydrolysis phosphatidylinositol 4,5-bisphosphate 2) Ca(2+)-induced release, process...

In the neurosecretory cell line PC12 cytosolic free Ca2+ concentration, [Ca2+]i, and membrane potential were affected by both external ATP nonapeptide bradykinin, BK. The latter caused a rapid large release of from intracellular stores (Ca2+ redistribution) and, in presence Ca2+, long lasting, but moderate influx, which was insensitive to dihydropyridine blockers. On contrary, evoked [Ca2+]i rise rapidly inactivated. At least three different mechanisms accounted for ATP-induced increase...

Mutations in amyloid precursor protein (APP), and presenilin-1 presenilin-2 (PS1 PS2) have causally been implicated Familial Alzheimer's Disease (FAD), but the mechanistic link between mutations early onset of neurodegeneration is still debated. Although no consensus has yet reached, most data suggest that both FAD-linked PS mutants endogenous PSs are involved cellular Ca2+ homeostasis. We here investigated subcellular handling primary neuronal cultures acute brain slices from wild type...

Calcium dynamics in astrocytes represent a fundamental signal that through gliotransmitter release regulates synaptic plasticity and behaviour. Here we present longitudinal study the PS2APP mouse model of Alzheimer's disease (AD) linking astrocyte Ca2+ hypoactivity to memory loss. At onset plaque deposition, somatosensory cortical AD female mice exhibit drastic reduction signaling, closely associated with decreased endoplasmic reticulum concentration reduced expression sensor STIM1. In...

Early diagnosis of Alzheimer's disease (AD) is a very challenging problem and has been attempted through data-driven methods in recent years. However, considering the inherent complexity decoding higher cognitive functions from spontaneous neuronal signals, these benefit incorporation multimodal data. This work proposes an ensembled machine learning model with explainability (EXML) to detect subtle patterns cortical hippocampal local field potential signals (LFPs) that can be considered as...

Capacitative calcium entry (CCE) has been described in a variety of cell types. To date, little is known about its role the CNS, and particular cross‐talk between glia neurons. We have first analyzed properties CCE astrocytes culture, comparison with that rat basophilic leukemia line (RBL‐2H3), model where release‐activated Ca 2+ (CRAC) channels unambiguously correlated CCE. here show (i) activated by store depletion influx induced glutamate share same pharmacological profile RBL‐2H3 cells...

We have previously shown that familial Alzheimer's disease mutants of presenilin-2 (PS2) and, to a lesser extent, presenilin-1 (PS1) lower the Ca(2+) concentration intracellular stores. here examined mechanism by which wild-type and mutant PS2 affect store handling. By using HeLa, SH-SY5Y MEFs as model cells, recombinant aequorins probes, we show evidence transient expression either or increases passive leakage: both ryanodine- IP(3)-receptors contribute exit out ER, whereas ribosome...

The functional characteristics of a nonacidic, inositol 1,4,5-trisphosphate- and thapsigargin-insensitive Ca2+ pool have been characterized in mammalian cells derived from the rat pituitary gland (GH3, GC, GH3B6), adrenal tissue (PC12), mast (RBL-1). This is released into cytoplasm by ionophores ionomycin or A23187 after discharge 1,4,5-trisphosphate-sensitive store with an agonist coupled to phospholipase C activation and/or thapsigargin. amount trapped within this increased significantly...