A5001635104- Cardiac electrophysiology and arrhythmias
- Ion channel regulation and function
- Neuroscience and Neural Engineering
- Neuroscience and Neuropharmacology Research
- Electrochemical Analysis and Applications
- Receptor Mechanisms and Signaling
- Cardiac Ischemia and Reperfusion
- Analytical Chemistry and Sensors
- Nicotinic Acetylcholine Receptors Study
- Advanced Fluorescence Microscopy Techniques
- Planarian Biology and Electrostimulation
- Cardiovascular Effects of Exercise
- Lipid Membrane Structure and Behavior
- Photoreceptor and optogenetics research
- Marine Ecology and Invasive Species
- Heart Rate Variability and Autonomic Control
- Plant and Biological Electrophysiology Studies
- Physiological and biochemical adaptations
- Insect and Pesticide Research
- Nanopore and Nanochannel Transport Studies
- Restless Legs Syndrome Research
- Ion Channels and Receptors
- Neurobiology and Insect Physiology Research
- Muscle activation and electromyography studies
- Plant Stress Responses and Tolerance
University of California, Merced
2014-2025
Rockefeller University
2021
Brigham Young University
2019
Rush University Medical Center
2015
University of Michigan
2014
Universidad Técnica Estatal de Quevedo
2010
Texas Tech University Health Sciences Center
2000-2006
Texas Tech University
2000-2006
Loyola University Chicago
2004
University of Wisconsin–Madison
2002
Despite extensive research, the mechanisms responsible for graded nature and early termination of Ca 2+ -induced release (CICR) from sarcoplasmic reticulum (SR) in cardiac muscle remain poorly understood. Suggested include cytosolic -dependent inactivation/adaptation luminal deactivtion SR channels/ryanodine receptors (RyRs). To explore importance versus regulatory controlling CICR, we assessed impact intra-SR buffering on global local properties patch-clamped or permeabilized rat...
AimsMyocardial stunning is a contractile dysfunction that occurs after brief ischaemic insult. Substantial evidence supports this triggered by Ca2+ overload during reperfusion. The aim of the present manuscript to define origin increase in intact heart.
Postnatal maturation of the rat heart is characterized by major changes in mechanism excitation-contraction (E-C) coupling. In neonate, t tubules and sarcoplasmic reticulum (SR) are not fully developed yet. Consequently, Ca(2+)-induced Ca(2+) release (CICR) does play a central role E-C most that triggers contraction comes through sarcolemma. this work, we defined contribution sarcolemmal entry released from SR to transient during first 3 wk postnatal development. To end, intracellular...
The role of ryanodine-sensitive intracellular Ca2+ stores present in nonmuscular cells is not yet completely understood. Here we examine the physiological parameters determining dynamics caffeine-induced release individual fura-2–loaded sympathetic neurons. Two components were distinguished: an early, transient (TR) and a delayed, persistent (PR). TR component shows refractoriness, depends on filling status store, requires caffeine concentrations ≥10 mM. Furthermore, it selectively...
Objective To investigate the importance of phosphorylation Ser16 and Thr17 sites phospholamban (PLN) on intracellular Ca2+ (Cai2+) handling contractile recovery stunned myocardium.
Stomatal movements depend on an osmoregulation process in which swelling or shrinking of the guard cells opens closes stomatal pore. Ions and water fluxes are essential aspect cell osmoregulation. Thus far, studies these have focused plasma membrane. Guard cells, however, a multi-compartment system that includes prominent vacuole, has primary role turgor regulation. This study reports detailed characterization ion channel at tonoplast Allium cepa (onion). We used patch-clamp methodology with...
Coupled gating (synchronous openings and closures) of groups skeletal muscle ryanodine receptors (RyR1), which mimics RyR1-mediated Ca 2+ release underlying sparks, was first described by Marx et al. (Marx SO, Ondrias K, Marks AR. Science 281: 818–821, 1998). The nature the RyR1-RyR1 interactions for coupled still needs to be characterized. Consequently, we defined planar lipid bilayer conditions where ∼25% multichannel reconstitutions contain mixtures independently RyR1. In ∼10% cases, all...
Ca(+)-induced Ca(2+) release tightly controls the function of ventricular cardiac myocytes under normal and pathological conditions. Two major factors contributing to regulation are cytosolic free concentration sarcoplasmic reticulum (SR) content. We hypothesized that amount released from SR during each heart beat strongly defines refractoriness release. To test this hypothesis, EGTA AM, a high-affinity, slow-association rate chelator, was used as tool modify luminal An analysis dynamics...
Assessing the underlying ionic currents during a triggered action potential (AP) in intact perfused hearts offers opportunity to link molecular mechanisms with pathophysiological problems cardiovascular research. The developed loose patch photolysis technique can provide striking new insights into cardiac function at whole heart level health and disease.To measure transmembrane an AP determine how when surface Ca(2+) influx that triggers Ca(2+)-induced release occurs Ca(2+)-activated...
A confocal spot detection optical setup was used to record fluorescence signals in response calcium pulses, elicited by flash photolysis of DM‐nitrophen, with the indicators CaOrange‐5N and Fluo‐3. Our results yield following conclusions: [Ca 2+ ] changes are almost perfect spikes at pCa 9 broader transients followed a step 7. The were measure dissociation rate constant Ca dyes. Experiments 7 verify kinetic constants dyes obtain those DM‐nitrophen. association this compound found be more...
Type-II ryanodine receptor channels (RYRs) play a fundamental role in intracellular Ca2+ dynamics heart. The processes of activation, inactivation, and regulation these have been the subject intensive research focus recent debates. Typically, approaches to understand involve statistical analysis single RYRs, involving signal restoration, model estimation, selection. These tasks are usually performed by following rather phenomenological criteria that turn models into self-fulfilling...
The ventricular action potential (AP) is characterized by a fast depolarizing phase followed repolarization that displays second upstroke known as 2. This generally not present in mouse myocytes. Thus we performed colocalized electrophysiological and optical recordings of APs Langendorff-perfused hearts founding noticeable Ryanodine well nifedipine reduced Our hypothesis current activated Ca 2+ released from the sarcoplasmic reticulum (SR) rather than “electrogenicity” L-type crucial...
Abstract The most compelling evidence for a functional role of caffeine‐sensitive intracellular Ca 2+ reservoirs in nerve cells derives from experiments on peripheral neurons. However, the properties their ryanodine receptor calcium release channels have not been studied. This work combines single‐cell fura‐2 microfluorometry, [ 3 H]ryanodine binding and recording to examine these stores rat sympathetic neurons superior cervical ganglion. Intracellular measurements showed that possess...
Mg 2+ , an important constituent of the intracellular milieu in cardiac myocytes, is known to inhibit ryanodine receptor (RyR) Ca release channels by competing with at cytosolic activation sites channel. However, significance this competition for local, dynamic -signaling processes thought govern excitation-contraction (EC) coupling remains largely unknown. In present study, stimuli different waveforms (i.e., sustained and brief) were generated photolysis caged compound nitrophenyl...