Search results for "Calcium Channel"
showing 10 items of 204 documents
Expression of genes encoding the calcium signalosome in cellular and transgenic models of Huntington's disease
2013
Huntington's disease (HD) is a hereditary neurodegenerative disease caused by the expansion of a polyglutamine stretch in the huntingtin (HTT) protein and characterized by dysregulated calcium homeostasis. We investigated whether these disturbances are correlated with changes in the mRNA level of the genes that encode proteins involved in calcium homeostasis and signaling (i.e., the calciosome). Using custom-made TaqMan low-density arrays containing probes for 96 genes, we quantified mRNA in the striatum in YAC128 mice, a model of HD, and wildtype mice. HTT mutation caused the increased expression of some components of the calcium signalosome, including calretinin, presenilin 2, and calmyri…
Intracellular Na+ concentration influences short-term plasticity of glutamate transporter-mediated currents in neocortical astrocytes.
2012
Fast synaptic transmission requires a rapid clearance of the released neurotransmitter from the extracellular space. Glial glutamate transporters (excitatory amino acid transporters, EAATs) strongly contribute to glutamate removal. In this work, we investigated the paired-pulse plasticity of synaptically activated, glutamate transporter-mediated currents (STCs) in cortical layer 2/3 astrocytes. STCs were elicited by local electrical stimulation in layer 4 in the presence of ionotropic glutamate (AMPA and NMDA), GABAA, and GABAB receptor antagonists. In experiments with low [Na+]i (5 mM) intrapipette solution, STCs elicited by paired-pulse stimulation demonstrated paired-pulse facilitation (…
Binding Sites for Ca2+‐Channel Effectors and Ryanodine inPeriplaneta americana—Possible Targets for New Insecticides
1996
The calcium channel and the 'calcium release channel' of muscle membrane of the cockroach Periplaneta americana have been characterized. Biological assays with calcium channel blockers and ryanodine on different insects and acari revealed pronounced insecticidal effects with ryanodine, but not with calcium channel blockers, at concentrations between 0.1 and 300 μg ml -1 . Skeletal muscle membranes derived either from the tubular network or from the sarcoplasmatic reticulum of P. americana were characterized with respect to the binding of the dihydropyridine (DHP) [ 3 H]isradipine (PN 200-110), the phenylalkylamine [ 3 H]verapamil and the alkaloid [ 3 H]ryanodine. Preliminary binding studies…
Memory-enhancing and brain protein expression-stimulating effects of novel calcium antagonist in Alzheimer’s disease transgenic female mice
2016
The prevalence of Alzheimer's disease (AD) is higher in females than in males, and causes more severe cognitive, memory and behavioral impairments. Previously, in male transgenic (Tg) APPSweDI mice, we reported that the novel lipophilic 1,4-dihydropyridine (DHP) derivative AP-12 crossed the blood-brain barrier, blocked neuronal and vascular calcium channels, changed brain protein expression and improved behavior. In this study, we used female Tg APPSweDI mice to assess the effects of AP-12 on behavior, and brain protein expression, with a particular focus on those of the GABAergic system. The results showed that in female Tg mice, similar to male Tg mice, AP-12 improved spatial learning/mem…
Impact of diet-induced obesity on the mouse brain phosphoproteome
2018
Obesity is closely associated to several diseases such as type 2 diabetes, cardiovascular disease, hepatic steatosis, airway disease, neurodegeneration, biliary diseases and certain cancers. It is, therefore, of importance to assess the role of nutrition in disease prevention as well as its effect in the course of such pathologies. In the present study, we addressed the impact of the exposure to different obesogenic diets in the mice brains phosphoproteome. To analyze if the obesity could be able to modify the protein pattern expression of brain neurons, obesity was induced in two different groups of mice. One group of mice was fed with hyperglycemic diet (HGD) and the other one was fed wit…
Histochemical localization of calcium ATPase in the cochlea of the guinea pig
1992
The activity of Ca(2+)-ATPase in the inner ear of the guinea pig was studied ultracytochemically by the lead citrate reaction. The electron-dense reaction products as an expression of Ca(2+)-ATPase activity were localized in endolymphatic cells of Reissner's membrane, in outer and inner hair cells and in some supporting cells. The main finding was the difference in the localization of Ca(2+)-ATPase in outer and inner hair cells. In the latter cells the activity sites were mainly intracellular and in apical membrane specializations, whereas in the outer hair cells the enzyme was localized in the apical membrane specializations and the basolateral plasma membrane.
Effect of the CB1 cannabinoid agonist WIN 55212-2 on the acquisition and reinstatement of MDMA-induced conditioned place preference in mice
2010
AbstractBackgroundNumerous reports indicate that MDMA users consume other psychoactive drugs, among which cannabis is one of the most common. The aim of the present study was to evaluate, using the conditioned place preference, the effect of the cannabinoid agonist WIN 55,212-2 on the rewarding effects of MDMA in mice.MethodsIn the first experiment adolescent mice were initially conditioned with 1.25, 2.5 or 5 mg/kg of MDMA or 0.1 or 0.5 mg/kg of WIN and subsequently with both drugs. Reinstatement of the extinguished preference by priming doses was performed in the groups that showed CPP. In the second experiment, animals were conditioned with 2.5 or 5 mg/kg of MDMA and, after extinction, r…
Capacitative Ca2+ entry associated with α1-adrenoceptors in rat aorta
1997
In rat aorta, depletion of internal Ca2+ stores by addition of noradrenaline (1 microM) induces a biphasic response (an initial phasic response and a tonic one) mediated by two different intracellular Ca2+ pools. This response cannot be repeated, suggesting a depletion of internal Ca2+ stores sensitive to noradrenaline. In absence of the agonist, this depletion is the signal for the entry of extracellular Ca2+, not only to refill the stores but also, under our experimental conditions, to activate the contractile proteins thus inducing an increase in the resting tone (IRT) that constitutes functional evidence of this Ca2+ entry. The ionic channels involved in the mechanism of the IRT have be…
Arginine Vasopressin Enhances Sympathetic Constriction Through the V 1 Vasopressin Receptor in Human Saphenous Vein
1998
Background —Arginine vasopressin (AVP) not only acts directly on blood vessels through V 1 receptor stimulation but also may modulate adrenergic-mediated responses in animal experiments in vivo and in vitro. The aim of the present study was to investigate whether AVP can contribute to an abnormal adrenergic constrictor response of human saphenous veins. Methods and Results —Saphenous vein rings were obtained from 32 patients undergoing coronary artery bypass surgery. The vein rings were suspended in organ bath chambers for isometric recording of tension. AVP (3×10 −9 mol/L) enhanced the contractions elicited by electrical field stimulation at 1, 2, and 4 Hz (by 80%, 70%, and 60%, respectiv…
Choice and Outcomes of Rate Control versus Rhythm Control in Elderly Patients with Atrial Fibrillation: A Report from the REPOSI Study
2018
Background: Among rate-control or rhythm-control strategies, there is conflicting evidence as to which is the best management approach for non-valvular atrial fibrillation (AF) in elderly patients. Design: We performed an ancillary analysis from the ‘Registro Politerapie SIMI’ study, enrolling elderly inpatients from internal medicine and geriatric wards. Methods: We considered patients enrolled from 2008 to 2014 with an AF diagnosis at admission, treated with a rate-control-only or rhythm-control-only strategy. Results: Among 1114 patients, 241 (21.6%) were managed with observation only and 122 (11%) were managed with both the rate- and rhythm-control approaches. Of the remaining 751 patie…