Cerebral ischemia stimulates Ca2+ influx and thus increases neuronal intracellular free [Ca2+]. Using a rat model of cerebral without recirculation, we tested whether enhances the activation by ryanodine receptor (RyR) channels, requisite feature RyR-mediated Ca2+-induced release (CICR). To this aim, evaluated how single RyR channels from endoplasmic reticulum vesicles, fused into planar lipid bilayers, responded to cytoplasmic [Ca2+] changes. Endoplasmic vesicles were isolated cortex brains...

We have previously reported that primary hippocampal neurons exposed to synaptotoxic amyloid beta oligomers (AβOs), which are likely causative agents of Alzheimer's disease (AD), exhibit abnormal Ca2+ signals, mitochondrial dysfunction and defective structural plasticity. Additionally, AβOs-exposed a decrease in the protein content type-2 ryanodine receptor (RyR2) channels, exert critical roles synaptic plasticity spatial memory processes. The antioxidant N-acetylcysteine (NAC) prevents...

Integrated electromyographic activity of masseter and anterior temporal muscles was recorded using bipolar surface electrodes in 33 young adults. Subjects were skeletally classified according to ANB angle reading corrected both for maxillary position rotation the jaw. Postural higher Class III subjects than I II, whereas II similar. During swallowing, muscle Classes not different between I. maximal voluntary clenching, among classes. High correlations as well with overjet observed. Skeletal...

The response of ryanodine receptor (RyR) channels to increases in cytoplasmic calcium concentration ([Ca2+]) is tuned by several mechanisms, including redox signaling. Three different responses [Ca2+] have been described RyR channels, low, moderate and high activity responses, which depend on channel protein oxidation state. Thus, reduced display the low response, whereas partially oxidized more response. As here, from rat brain cortex or hippocampus displayed aged-related marked changes...

The response of ryanodine receptor (RyR) channels to increases in free cytoplasmic calcium concentration ([Ca2+]) is tuned by several mechanisms, including redox signaling. Three different responses [Ca2+] have been described RyR channels, low, moderate and high activity responses, which depend on the channel protein oxidation state. Thus, reduced display low response, whereas partially oxidized more response. As here, from rat brain cortices or hippocampi displayed aged-related marked...

Calcium channels derived from sarcoplasmic reticulum of frog skeletal muscle were fused with planar lipid bilayers. Fractional open times displayed two types calcium dependence: (i) blockable showed a bell‐shaped dependence an activation constant 4.5 μM, Hill coefficient for 1.46 and blocking 226 (ii) non‐blockable sigmoidal 1.1 μM 1.42; no effect was seen up to 0.5 mM. These may underlie the coexistence different pathways release in muscle.

Ventricular arrhythmias are a common cause of sudden cardiac death, and their occurrence is higher in obese subjects. Abnormal gating ryanodine receptors (RyR2), the calcium release channels sarcoplasmic reticulum, can produce ventricular arrhythmias. Since obesity promotes oxidative stress RyR2 redox-sensitive channels, we investigated whether activity was altered mice. Mice fed high fat diet (HFD) became after eight weeks exhibited significant increase Single isolated from hearts mice were...

We have reported that ryanodine receptor (RyR) channels display three different responses to cytoplasmic free Ca 2 + concentration ([Ca ]) depending on their redox state (Marengo JJ, Hidalgo C, and Bull R. Biophys J 74: 1263–1277, 1998), with low, moderate, high maximal fractional open times ( P o ). Activation by ATP of single RyR from rat brain cortex was tested in planar lipid bilayers 10 or 0.1 μM [Ca ]. At ], low- presented lower apparent affinity activation [[ATP] for half-maximal K...

Despite their relevance for neuronal Ca 2+ -induced release (CICR), activation by of ryanodine receptor (RyR) channels brain endoplasmic reticulum at the [ATP], [Mg ], and redox conditions present in neurons has not been reported. Here, we studied effects varying cis-(cytoplasmic) free ATP concentration ([ATP]), RyR state on dependence from rat cortex. At pCa 4.9 0.5 mM adenylylimidodiphosphate (AMP-PNP), increasing ] up to 1 inhibited vesicular [ 3 H]ryanodine binding; incubation with...

Adenosine 5'-cyclic diphosphoribose [cyclic ADP-ribose (cADPR)], a metabolite of NAD+ that promotes Ca2+ release from sea urchin egg homogenates and microsomal fractions, has been proposed to act as an endogenous agonist in eggs. We describe experiments showing fraction isolated Tetrapigus nyger eggs displayed Ca(2+)-selective single channels with conductances 155.0 +/- 8.0 pS asymmetric Cs+ solutions 47.5 1.1 solutions. These were sensitive stimulation by Ca2+, ATP, caffeine, but not...

Unlike apoptosis, mechanisms leading to necrosis are less well understood. Moreover, changes in as a function of age have not been studied human lymphocytes. H(2)O(2)-induced death peripheral lymphocytes (56 healthy donors, 24-95 years) was evaluated by flow cytometry and propidium iodide staining, caspase activation, DNA laddering, electron microscopy. stress associated with high levels young individuals (≤30 years), whereas progressively enhanced apoptotic observed older without overall...

This study compares the electromyographic (EMG) activity of muscles from lips and hyoid bone in subjects with or without lip competence.Two groups 20 each, competence were studied. EMG superior orbicularis oris (SOO), inferior (IOO), suprahyoid (SH) infrahyoid (IH) was recorded subject seated upright position during following tasks: (1) at rest; (2) speaking; (3) swallowing; (4) forced deep breathing; (5) maximal voluntary clenching; (6) chewing.EMG significantly higher competent than SOO...

Summary An analysis of integrated electromyographic (IEMG) activity masseter and anterior temporal muscles was undertaken in fifteen patients with complete dentures eight adult subjects natural dentition. Bipolar surface electrodes were used for IEMG recordings during maximal voluntary clenching saliva swallowing the inter‐cuspal position. The both significantly lower than During similar groups. This may have a great clinical significance maintenance functional state different structures...

An analysis of integrated electromyographic (IEMG) activity the superior orbicularis oris muscle was undertaken in 15 children with cleft lip and palate who have undergone surgery compared to 10 without clefts (control group). Bipolar surface electrodes were used for IEMG recordings resting level during swallowing saliva. Similar observed both groups. During saliva, higher than (noncleft children). Moreover, group, abnormal seal showed highest values This fact suggests that each swallow a...

Abstract The effects of anisomycin (ANM) on newborn chicks have been studied with respect to brain protein synthesis, growth, EEG, toxicity, and several passive avoidance learning tasks. It was found that intracerebral ANM (80 nmol) gave a maximum inhibition synthesis 30%, while combination subcutaneous (10 μmol; 53 mg/kg) plus nmol; 21 μg) ANM, inhibited by 91% in the first 2 hr 75% subsequent period. Cycloheximide (CXM) also combined injections at same doses as 97% 4 followed injection....

1. The modulation by Ca2+ of the activation inositol 1,4,5‐trisphosphate (IP3) channels present in native sarcoplasmic reticulum membranes from frog skeletal muscle was studied after channel incorporation into planar phospholipid bilayers presence or Ba2+ as current carrier species. 2. Channel activity expressed fractional open time (Po) low (less than equal to 0.15) varying free concentrations bathing myoplasmic face (cis side), and did not increase significantly between 0.01 30...

Endoplasmic reticulum vesicles isolated from rat brain cortex and fused with lipid bilayers displayed ryanodine‐sensitive calcium channels, three cytoplasmic dependences. A: Channels ( n = 5) stimulated by Ca 2+ K 0.5 1.2 μ M Hill 1.9) not inhibited up to mM . B: 14) cooperatively activated 6.9 1.8), 152 1.8). C: Low P o (< 0.1) channels 22), non‐cooperatively the same 26.3 These types of responses [Ca ] may underlie separate release pathways in neurons cortex.