Microelectrodes
Ion-Selective Electrodes
Membrane Potentials
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
Electrochemistry
Electrophysiology
Action Potentials
Potassium
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
Extracellular Space
Electrodes, Implanted
Electrochemical Techniques
Hydrogen-Ion Concentration
Sodium
Bicarbonates
Strophanthidin
Electrodes
Helix (Snails)
Necturus
Micromanipulation
Necturus maculosus
Purkinje Fibers
Conductometry
Glass
Equipment Failure Analysis
Dielectric Spectroscopy
A technique of measuring the dielectric properties of materials, which vary over a range of frequencies depending on the physical properties of the material. The technique involves measuring, over a range of frequencies, ELECTRICAL IMPEDANCE and phase shift of an electric field as it passes through the material.
Neurons
Guinea Pigs
Leeches
Carbon
Diamond
Potentiometry
Biosensing Techniques
Ion Transport
Partial Pressure
Cats
The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)
Calcium
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
Oxygen
Polarography
An electrochemical technique for measuring the current that flows in solution as a function of an applied voltage. The observed polarographic wave, resulting from the electrochemical response, depends on the way voltage is applied (linear sweep or differential pulse) and the type of electrode used. Usually a mercury drop electrode is used.
4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
Ion Exchange
Quaternary Ammonium Compounds
Ethoxzolamide
Amiloride
A pyrazine compound inhibiting SODIUM reabsorption through SODIUM CHANNELS in renal EPITHELIAL CELLS. This inhibition creates a negative potential in the luminal membranes of principal cells, located in the distal convoluted tubule and collecting duct. Negative potential reduces secretion of potassium and hydrogen ions. Amiloride is used in conjunction with DIURETICS to spare POTASSIUM loss. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p705)
Cortical Spreading Depression
Papillary Muscles
Benzolamide
Evoked Potentials
Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.
Ouabain
Patch-Clamp Techniques
An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.
Barium
Carbonic Anhydrase Inhibitors
Sodium-Bicarbonate Symporters
Dark Adaptation
Microtechnology
Manufacturing technology for making microscopic devices in the micrometer range (typically 1-100 micrometers), such as integrated circuits or MEMS. The process usually involves replication and parallel fabrication of hundreds or millions of identical structures using various thin film deposition techniques and carried out in environmentally-controlled clean rooms.
Iontophoresis
Therapeutic introduction of ions of soluble salts into tissues by means of electric current. In medical literature it is commonly used to indicate the process of increasing the penetration of drugs into surface tissues by the application of electric current. It has nothing to do with ION EXCHANGE; AIR IONIZATION nor PHONOPHORESIS, none of which requires current.
Rana pipiens
Buffers
Tetrodotoxin
Rabbits
Extracellular Fluid
Biological Transport, Active
Heart Conduction System
Ions
Endolymph
Rats, Sprague-Dawley
Acid-Base Equilibrium
Ion Channels
Alkalies
Rana esculenta
Silicon
Retina
The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.
Nanocomposites
Perilymph
Synaptic Transmission
The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.
Cell Membrane Permeability
Gold
Ganglia
Dopamine
One of the catecholamine NEUROTRANSMITTERS in the brain. It is derived from TYROSINE and is the precursor to NOREPINEPHRINE and EPINEPHRINE. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement. A family of receptors (RECEPTORS, DOPAMINE) mediate its action.
Rana temporaria
Carbon Dioxide
Osmolar Concentration
Brain
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
Oxygen Consumption
Photoreceptor Cells
Specialized cells that detect and transduce light. They are classified into two types based on their light reception structure, the ciliary photoreceptors and the rhabdomeric photoreceptors with MICROVILLI. Ciliary photoreceptor cells use OPSINS that activate a PHOSPHODIESTERASE phosphodiesterase cascade. Rhabdomeric photoreceptor cells use opsins that activate a PHOSPHOLIPASE C cascade.
Sinoatrial Node
The small mass of modified cardiac muscle fibers located at the junction of the superior vena cava (VENA CAVA, SUPERIOR) and right atrium. Contraction impulses probably start in this node, spread over the atrium (HEART ATRIUM) and are then transmitted by the atrioventricular bundle (BUNDLE OF HIS) to the ventricle (HEART VENTRICLE).
Electroencephalography
Dimethylpolysiloxanes
Silicone polymers which consist of silicon atoms substituted with methyl groups and linked by oxygen atoms. They comprise a series of biocompatible materials used as liquids, gels or solids; as film for artificial membranes, gels for implants, and liquids for drug vehicles; and as antifoaming agents.
Ammonium Chloride
Motion
Dogs
Calibration
Cell Membrane
Microchemistry
Platinum
Platinum. A heavy, soft, whitish metal, resembling tin, atomic number 78, atomic weight 195.09, symbol Pt. (From Dorland, 28th ed) It is used in manufacturing equipment for laboratory and industrial use. It occurs as a black powder (platinum black) and as a spongy substance (spongy platinum) and may have been known in Pliny's time as "alutiae".
Potassium Channels
Peroneal Nerve
Mechanoreceptors
Acetylcholine
Muscle Contraction
Prostheses and Implants
Artificial substitutes for body parts, and materials inserted into tissue for functional, cosmetic, or therapeutic purposes. Prostheses can be functional, as in the case of artificial arms and legs, or cosmetic, as in the case of an artificial eye. Implants, all surgically inserted or grafted into the body, tend to be used therapeutically. IMPLANTS, EXPERIMENTAL is available for those used experimentally.
Diffusion
Quinidine
An optical isomer of quinine, extracted from the bark of the CHINCHONA tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular ACTION POTENTIALS, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission.
Potassium Channel Blockers
Submucous Plexus
One of two ganglionated neural networks which together form the enteric nervous system. The submucous (Meissner's) plexus is in the connective tissue of the submucosa. Its neurons innervate the epithelium, blood vessels, endocrine cells, other submucosal ganglia, and myenteric ganglia, and play an important role in regulating ion and water transport. (From FASEB J 1989;3:127-38)
Osmosis
Skin Physiological Phenomena
Potassium Chloride
Rats, Inbred Strains
Artifacts
Any visible result of a procedure which is caused by the procedure itself and not by the entity being analyzed. Common examples include histological structures introduced by tissue processing, radiographic images of structures that are not naturally present in living tissue, and products of chemical reactions that occur during analysis.
Chromaffin Cells
Cells that store epinephrine secretory vesicles. During times of stress, the nervous system signals the vesicles to secrete their hormonal content. Their name derives from their ability to stain a brownish color with chromic salts. Characteristically, they are located in the adrenal medulla and paraganglia (PARAGANGLIA, CHROMAFFIN) of the sympathetic nervous system.
Exocytosis
Nifedipine
Muscle, Smooth
Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)
Rana catesbeiana
Models, Biological
Acidosis
Anura
Somatosensory Cortex
Caffeine
A methylxanthine naturally occurring in some beverages and also used as a pharmacological agent. Caffeine's most notable pharmacological effect is as a central nervous system stimulant, increasing alertness and producing agitation. It also relaxes SMOOTH MUSCLE, stimulates CARDIAC MUSCLE, stimulates DIURESIS, and appears to be useful in the treatment of some types of headache. Several cellular actions of caffeine have been observed, but it is not entirely clear how each contributes to its pharmacological profile. Among the most important are inhibition of cyclic nucleotide PHOSPHODIESTERASES, antagonism of ADENOSINE RECEPTORS, and modulation of intracellular calcium handling.
Cerebral Cortex
Ammonia
Astacoidea
Hydrogen
The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight [1.00784; 1.00811]. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.
Serotonin
A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator.
Biological Transport
Acids
Chemical compounds which yield hydrogen ions or protons when dissolved in water, whose hydrogen can be replaced by metals or basic radicals, or which react with bases to form salts and water (neutralization). An extension of the term includes substances dissolved in media other than water. (Grant & Hackh's Chemical Dictionary, 5th ed)
Mathematics
Fluorescent Dyes
Synapses
Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.
Rats, Wistar
Sodium-Potassium-Exchanging ATPase
An enzyme that catalyzes the active transport system of sodium and potassium ions across the cell wall. Sodium and potassium ions are closely coupled with membrane ATPase which undergoes phosphorylation and dephosphorylation, thereby providing energy for transport of these ions against concentration gradients.
Xenopus laevis
Isoproterenol
Electrophysiological Phenomena
Chloride-Bicarbonate Antiporters
Electroneutral chloride bicarbonate exchangers that allow the exchange of BICARBONATE IONS exchange for CHLORIDE IONS across the cellular membrane. The action of specific antiporters in this class serve important functions such as allowing the efficient exchange of bicarbonate across red blood cell membranes as they passage through capillaries and the reabsorption of bicarbonate ions by the kidney.
Molecular dynamics of the sodium channel pore vary with gating: interactions between P-segment motions and inactivation. (1/2595)
Disulfide trapping studies have revealed that the pore-lining (P) segments of voltage-dependent sodium channels undergo sizable motions on a subsecond time scale. Such motions of the pore may be necessary for selective ion translocation. Although traditionally viewed as separable properties, gating and permeation are now known to interact extensively in various classes of channels. We have investigated the interaction of pore motions and voltage-dependent gating in micro1 sodium channels engineered to contain two cysteines within the P segments. Rates of catalyzed internal disulfide formation (kSS) were measured in K1237C+W1531C mutant channels expressed in oocytes. During repetitive voltage-clamp depolarizations, increasing the pulse duration had biphasic effects on the kSS, which first increased to a maximum at 200 msec and then decreased with longer depolarizations. This result suggested that occupancy of an intermediate inactivation state (IM) facilitates pore motions. Consistent with the known antagonism between alkali metals and a component of slow inactivation, kSS varied inversely with external [Na+]o. We examined the converse relationship, namely the effect of pore flexibility on gating, by measuring recovery from inactivation in Y401C+E758C (YC/EC) channels. Under oxidative conditions, recovery from inactivation was slower than in a reduced environment in which the spontaneous YC/EC cross-link is disrupted. The most prominent effects were slowing of a component with intermediate recovery kinetics, with diminution of its relative amplitude. We conclude that occupancy of an intermediate inactivation state facilitates motions of the P segments; conversely, flexibility of the P segments alters an intermediate component of inactivation. (+info)Cerebellar Purkinje cell simple spike discharge encodes movement velocity in primates during visuomotor arm tracking. (2/2595)
Pathophysiological, lesion, and electrophysiological studies suggest that the cerebellar cortex is important for controlling the direction and speed of movement. The relationship of cerebellar Purkinje cell discharge to the control of arm movement parameters, however, remains unclear. The goal of this study was to examine how movement direction and speed and their interaction-velocity-modulate Purkinje cell simple spike discharge in an arm movement task in which direction and speed were independently controlled. The simple spike discharge of 154 Purkinje cells was recorded in two monkeys during the performance of two visuomotor tasks that required the animals to track targets that moved in one of eight directions and at one of four speeds. Single-parameter regression analyses revealed that a large proportion of cells had discharge modulation related to movement direction and speed. Most cells with significant directional tuning, however, were modulated at one speed, and most cells with speed-related discharge were modulated along one direction; this suggested that the patterns of simple spike discharge were not adequately described by single-parameter models. Therefore, a regression surface was fitted to the data, which showed that the discharge could be tuned to specific direction-speed combinations (preferred velocities). The overall variability in simple spike discharge was well described by the surface model, and the velocities corresponding to maximal and minimal discharge rates were distributed uniformly throughout the workspace. Simple spike discharge therefore appears to integrate information about both the direction and speed of arm movements, thereby encoding movement velocity. (+info)Neural encoding in orbitofrontal cortex and basolateral amygdala during olfactory discrimination learning. (3/2595)
Orbitofrontal cortex (OFC) is part of a network of structures involved in adaptive behavior and decision making. Interconnections between OFC and basolateral amygdala (ABL) may be critical for encoding the motivational significance of stimuli used to guide behavior. Indeed, much research indicates that neurons in OFC and ABL fire selectively to cues based on their associative significance. In the current study recordings were made in each region within a behavioral paradigm that allowed comparison of the development of associative encoding over the course of learning. In each recording session, rats were presented with novel odors that were informative about the outcome of making a response and had to learn to withhold a response after sampling an odor that signaled a negative outcome. In some cases, reversal training was performed in the same session as the initial learning. Ninety-six of the 328 neurons recorded in OFC and 60 of the 229 neurons recorded in ABL exhibited selective activity during evaluation of the odor cues after learning had occurred. A substantial proportion of those neurons in ABL developed selective activity very early in training, and many reversed selectivity rapidly after reversal. In contrast, those neurons in OFC rarely exhibited selective activity during odor evaluation before the rats reached the criterion for learning, and far fewer reversed selectivity after reversal. The findings support a model in which ABL encodes the motivational significance of cues and OFC uses this information in the selection and execution of an appropriate behavioral strategy. (+info)Correlated firing in rabbit retinal ganglion cells. (4/2595)
A ganglion cell's receptive field is defined as that region on the retinal surface in which a light stimulus will produce a response. While neighboring ganglion cells may respond to the same stimulus in a region where their receptive fields overlap, it generally has been assumed that each cell makes an independent decision about whether to fire. Recent recordings from cat and salamander retina using multiple electrodes have challenged this view of independent firing by showing that neighboring ganglion cells have an increased tendency to fire together within +/-5 ms. However, there is still uncertainty about which types of ganglion cells fire together, the mechanisms that produce coordinated spikes, and the overall function of coordinated firing. To address these issues, the responses of up to 80 rabbit retinal ganglion cells were recorded simultaneously using a multielectrode array. Of the 11 classes of rabbit ganglion cells previously identified, coordinated firing was observed in five. Plots of the spike train cross-correlation function suggested that coordinated firing occurred through two mechanisms. In the first mechanism, a spike in an interneuron diverged to produce simultaneous spikes in two ganglion cells. This mechanism predominated in four of the five classes including the ON brisk transient cells. In the second mechanism, ganglion cells appeared to activate each other reciprocally. This was the predominant pattern of correlated firing in OFF brisk transient cells. By comparing the receptive field profiles of ON and OFF brisk transient cells, a peripheral extension of the OFF brisk transient cell receptive field was identified that might be produced by lateral spike spread. Thus an individual OFF brisk transient cell can respond both to a light stimulus directed at the center of its receptive field and to stimuli that activate neighboring OFF brisk transient cells through their receptive field centers. (+info)Thapsigargin inhibits a potassium conductance and stimulates calcium influx in the intact rat lens. (5/2595)
1. An increase in lens cell calcium has long been associated with cortical cataract. Recently, it has been shown that thapsigargin induces a rise in lens cell calcium by release from endoplasmic reticulum stores. The effects of this rise on the optical and membrane characteristics of the lens were studied in the isolated rat lens. 2. The electrical characteristics of the isolated, perifused rat lens were measured using a two-internal microelectrode technique that permits measurement of plasma membrane conductance (Gm), membrane potential (Vm) and junctional conductance in the intact lens. 3. Thapsigargin (1 microM) induced a rapid overall depolarization of Vm that was accompanied by first a decrease and then an increase in Gm. 4. Replacing external Na+ with tetraethylammonium (TEA) abolished the decrease in Gm. However, a transient increase phase was still observed. 5. The changes in conductance were further characterized by measuring 22Na+ and 45Ca2+ influxes into the isolated lens. Thapsigargin (1 microM) induced a transient increase in 45Ca2+, but did not affect Na+ influx. 6. The Ca2+ channel blocker La3+ (10 microM) totally inhibited the thapsigargin-induced Ca2+ influx. It also blocked the increase in Gm observed in control and in Na+-free-TEA medium. In the absence of external calcium, thapsigargin induced a small depolarization in Vm. 7. These data indicate that thapsigargin induces both a decrease in K+ conductance and an increase in Ca2+ conductance. These probably result from release of stored Ca2+ and subsequent activation of store-operated Ca2+ channels (capacitative Ca2+ entry). 8. Thapsigargin application over the time course of these experiments (24 h) had no effect on junctional conductance or on the transparency of the lens. (+info)Nitric oxide release in penile corpora cavernosa in a rat model of erection. (6/2595)
1. Nitric oxide (NO) levels were measured in the corpus cavernosum of urethane-anaesthetized rats by using differential normal pulse voltammetry with carbon fibre microelectrodes coated with a polymeric porphyrin and a cation exchanger (Nafion). A NO oxidation peak could be recorded at 650 mV vs. a Ag-AgCl reference electrode every 100 s. 2. This NO signal was greatly decreased by the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME), given by local and systemic routes, and enhanced by the NO precursor L-arginine. Treatment with L-arginine reversed the effect of L-NAME on the NO peak. 3. Both the NO signal and the intracavernosal pressure (ICP) were increased by electrical stimulation of cavernosal nerves (ESCN). However, the rise in the NO levels long outlived the rapid return to baseline of the ICP values at the end of nerve stimulation. 4. The ICP and the NO responses to ESCN were suppressed by local and systemic injections of L-NAME. Subsequent treatment with L-arginine of L-NAME-treated animals restored the NO signal to basal levels and the NO response to ESCN. The ICP response to ESCN was restored only in part by L-arginine. 5. The observed temporal dissociation between the NO and ICP responses could be accounted for by several factors, including the buffering of NO by the blood filling the cavernosal spaces during erection. 6. These findings indicate that an increased production of NO in the corpora cavernosa is necessary but not sufficient for maintaining penile erection and suggest a complex modulation of the NO-cGMP-cavernosal smooth muscle relaxation cascade. (+info)In vitro simultaneous measurements of relaxation and nitric oxide concentration in rat superior mesenteric artery. (7/2595)
1. The relationship between nitric oxide (NO) concentration measured with an NO-specific microelectrode and endothelium-dependent relaxation was investigated in isolated rat superior mesenteric artery contracted with 1 microM noradrenaline. 2. Acetylcholine (10 microM) induced endothelium-dependent simultaneous increases in luminal NO concentration of 21 +/- 6 nM, and relaxations with pD2 values and maximum of 6.95 +/- 0.32 and 97.5 +/- 0.7 % (n = 7), respectively. An inhibitor of NO synthase, N G-nitro-L-arginine (L-NOARG, 100 microM) inhibited the relaxations and increases in NO concentration induced by acetylcholine. 3. Oxyhaemoglobin (10 microM) reversed the relaxations and increases in NO concentrations induced by acetylcholine, S-nitroso-N-acetylpenicillamine (SNAP) and S-morpholino-sydnonimine (SIN-1), but not the relaxations induced with forskolin. Oxyhaemoglobin also decreased the NO concentration below baseline level. 4. In the presence of L-NOARG (100 microM), a small relaxation to acetylcholine (10 microM) of noradrenaline-contracted segments was still seen; oxyhaemogobin inhibited this relaxation and decreased the NO concentration by 14 +/- 4 nM (n = 4). 5. The NO concentration-relaxation relationship for acetylcholine resembled that for SNAP and SIN-1 more than for authentic NO. Thus while 7-17 nM NO induced half-maximal relaxations in response to SNAP or SIN-1, 378 +/- 129 nM NO (n = 4) was needed for half-maximal relaxation to authentic NO. 6. The present study provides direct evidence that the relaxation of the rat superior mesenteric artery with the endothelium-dependent vasodilator acetylcholine is correlated to the endogeneous release of NO. The study also suggests that NO mediates the L-NOARG-resistant relaxations in this artery, and that there is a basal NO release. (+info)Firing properties of single vasoconstrictor neurones in human subjects with high levels of muscle sympathetic activity. (8/2595)
1. Single-unit recordings were made from 19 postganglionic muscle vasoconstrictor axons via tungsten microelectrodes in the peroneal nerve in seven healthy subjects with many multi-unit sympathetic discharges at rest ('high group', 75 +/- 5 multi-unit bursts per 100 heart beats, mean +/- s.e.m.). The results were compared with previous data from 14 units in subjects with 21 +/- 2 multi-unit bursts per 100 heart beats ('low group'). 2. In the 'high group' the units fired spontaneously in 35 +/- 4 % of all cardiac intervals. One unit only ever fired once per cardiac interval, 14 units (74 %) generated maximally two to three spikes, and four units (21 %) up to four to five spikes. Of those cardiac intervals in which a unit fired, a single spike occurred in 78 %, two spikes in 18 %, three spikes in 4 % and four spikes in less than 1 % of cardiac intervals. Measured as the inverse of all interspike intervals, the mean rate was 0.33 +/- 0.04 Hz and the mean intraburst frequency 22.2 +/- 1.6 Hz. Most results were similar to those in the 'low group', but in the 'low group' heart rate was higher (64.5 vs. 50.4 beats min-1) and mean firing frequency was higher (0.49 +/- 0.06 Hz). 3. During increases of multi-unit burst activity evoked by sustained inspiratory-capacity apnoea the firing probability of nine units in the 'high group' increased from 33 +/- 6 to 56 +/- 3 % of the cardiac intervals. Simultaneously, the incidence of single spikes decreased and the incidence of multiple spikes per cardiac interval increased, resulting in an increase of mean firing frequency from 0. 23 +/- 0.04 Hz at rest to 1.04 +/- 0.14 Hz during the apnoea. 4. We conclude that single muscle vasoconstrictor neurones usually fire only a solitary spike during sympathetic bursts both in subjects with a high and in subjects with a low number of bursts at rest. Presumably, differences in the numbers of bursts are due mainly to differences in firing probability and recruitment of sympathetic fibres. During acute increases of multi-unit activity, both increases in discharge frequency and recruitment of additional neurones contribute to the increased intensity of an individual sympathetic burst. (+info)
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Microfabrication of Pt-tip microelectrodes - RERO DOC
The total height of these microelectrodes is 47 μm, of which the upper 20 or 2 μm, respectively, are exposed Pt tips with a ... This paper describes the realization of Pt-tip microelectrodes by using microfabrication technology. ... Microfabrication of Pt-tip microelectrodes Thiébaud, P. ; Beuret, C. ; de Rooij, Nicolaas F. ; Koudelka-Hep, Milena In: Sensors ... Pt-tip microelectrodes ; Microfabrication technology ; Si anisotropic etching. OAI-PMH Identifier. *oai:doc.rero.ch: ...
Electrochemical characterizations of carbon nanomaterials by the cavity microelectrode technique - Nanomaterials Group
The CiPA Microelectrode Array Assay with hSC-Derived Cardiomyocytes: Current Protocol, Future Potential | Axion Biosystems
The CiPA Microelectrode Array Assay with hSC-Derived Cardiomyocytes: Current Protocol, Future Potential ... The CiPA Microelectrode Array Assay with hSC Derived Cardiomyocytes: Current Protocol, Future Potential ... Cross-site reliability of human induced pluripotent stem-cell derived cardiomyocyte based safety assays using microelectrode ... chapter details the current CiPA protocol for evaluating drug-induced changes in hSC-CM electrophysiology using microelectrode ...
Microelectrode Recordings in Deep Brain Stimulation Surgery - MIT Press Scholarship
... physiological localization using microelectrode recordings, and macrostimulation techniques. We summarize the standard ... Microelectrode Recordings in Deep Brain Stimulation Surgery. Chapter:. (p.275) 15 Microelectrode Recordings in Deep Brain ... Ethical and Practical Considerations for Human Microelectrode Recording Studies * 5. Subchronic In Vivo Human Microelectrode ... Ethical and Practical Considerations for Human Microelectrode Recording Studies * 5. Subchronic In Vivo Human Microelectrode ...
AC ELECTROHYDRODYNAMICS PHENOMENON IN 2D AND 3D MICROELECTRODES
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SCAN-Lab Technical Notes 06: Ultra Micro-Electrodes (UMEs) for SECM techniques - Biologic
SCAN Lab TN6 Ultra Micro Electrodes UMEs for SECM techniques You cannot access this resource because you are not logged in. Log ... SCAN-Lab Technical Notes 06: Ultra Micro-Electrodes (UMEs) for SECM techniques Latest updated: May 18, 2021 Introduction ... chevron_rightSCAN-Lab Technical Notes 06: Ultra Micro-Electrodes (UMEs) for SECM techniques ...
HKU Scholars Hub: Micro-electrodes for in situ temperature and bio-impedance measurement
High Gain Differential Microelectrode AC Amplifier Model 1800 (A-M Systems)
Electrochemical impedance spectroscopy and morphological analyses of pyrrole, phenylpyrrole and methoxyphenylpyrrole on carbon...
Effects of localized stimulation by means of microelectrodes of the cardioinhibitory vagal center in Rana esculenta]. -...
Amperometric detection of Enterobacteriaceae in river water by measuring β-galactosidase activity at interdigitated...
... detection of Enterobacteriaceae in river water by measuring β-galactosidase activity at interdigitated microelectrode arrays. ... detection of Enterobacteriaceae in river water by measuring β-galactosidase activity at interdigitated microelectrode arrays, ... detection of Enterobacteriaceae in river water by measuring β-galactosidase activity at interdigitated microelectrode arrays. ... are compared for the detection of faecal contamination in water using amperometry at gold interdigitated microelectrodes. They ...
Micro Electrode Array Market Key Players Analysis by 2025: MaxWell Biosystems, Smart Ephys, Axion Biosystems, Multi Channel...
There several aspects responsible for the ups and downs in the Micro Electrode Array industry dynamics. The global Micro ... The global Micro Electrode Array market research includes insightful data based on the demands of the market at different times ... Micro Electrode Array Market Key Players Analysis by 2025: MaxWell Biosystems, Smart Ephys, Axion Biosystems, Multi Channel ... "The document on the global Micro Electrode Array market is aimed to offer data regarding the competitive arena of the business ...
Microfluidic Devices Fabrication for Bioelectrokinetic System Applications | IntechOpen
A bonded microelectrodes array with dimensions. The width of the device is 2.0 cm and length is 2.5 cm. The 5 mm length each ... the thickness of the microelectrode and microchannel. In fabrication of microfluidic the microelectrode and microchannel ... The microelectrode will be deposited on the glass wafer by using the electron beam lithography. This technique will ensure the ... Microelectrodes on the glass were patterned using photolithography and ion beam milling over titanium, Ti, seed layer. Pt or Au ...
Sam Musallam - Search Results - PubMed
Neural Information Processing - 21st International Conference, ICONIP 2014, Kuching, Malaysia, November 3-6, 2014. Proceedings,...
Archive for September 2010
Implantable Microelectrodes. Bio Medical Micro Devices (BioMEMS) research at UBC works to miniaturize systems or devices, such ... Implantable Microelectrodes research attempts to increase biocompatibility of implants used for extended periods […] ... The research focuses on areas including Implantable Microelectrodes, Chemical Sensors and Microfludic Devices. ...
A flexible electrochemical micro lab-on-chip: application to the detection of interleukin-10 - Archive ouverte HAL
The microelectrodes were manufactured on PI by a combination of soft lithographical tools. To produce an operational mu LoC, a ... Cyclic voltammetry was applied as the characterization technique for the gold microelectrode surface properties. Finally, ... a mu LoC containing eight gold microelectrodes based on a polyimide (PI) substrate was fabricated. ... a mu LoC containing eight gold microelectrodes based on a polyimide (PI) substrate was fabricated. The microelectrodes were ...
SISIUS: Ficha personal: Antonio Ramos Reyes
Electrohydrodynamics in Microelectrode Structures. En: Institute of Physics Conference Series. 2004. N m. 178. Pag. 175-180 ... AC Electric-Field-Induced Fluid Flow in Microelectrodes. En: Journal of Colloid and Interface Science. 1999. Vol. 217. N m. 2. ... Electrothermally Induced Fluid Flow on Microelectrodes. En: Journal of Electrostatics. 2001. Vol. 53. N m. 2. Pag. 71-87 Morgan ... Fluid Flow Driven by A.C. Electric Fields in Microelectrodes. En: Institute of Physics Conference Series. 1999. Vol. 163. Pag. ...
KAKEN - Research Projects | Femtosecond laser 3-D microfabrication of inorganic materaials and its photonic application ...
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Irig's electronic nose is now even more discerning - MINATEC
IEDM 2020 online conference now has its own online workshop - MINATEC
Tomorrow's window glass could be photochromic and photovoltaic - MINATEC
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Education at MINATEC - MINATEC
Neurotoxicology and Safety Assays | Axion Biosystems
USA prices | Kation Scientific
CDE series carbon disc microelectrodes. Order No. Description Unit USD CDE1000-3 Carbon disc microelectrode, 10 μm (diameter) ... CFE series carbon fiber microelectrodes. Order No. Description Unit USD CFE10100-3 Carbon fiber microelectrode, 10 μm x 100 μm ... Implantable CF Microelectrode. Spikelmplant-1 Implantable miniature carbon fiber microelectrode. Order No. Description Unit USD ... Carbon disc microelectrode, 10 μm (diameter) Box of 10 $ 600.00 CDE1000-20 Carbon disc microelectrode, 10 μm (diameter) Box of ...
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Arrays9
- Microelectrode arrays (MEA), also known as multielectrode arrays, contain a grid of tightly spaced electrodes embedded in the culture surface of the well. (axionbiosystems.com)
- In this thesis, microelectrode arrays of micropumps have been designed, fabricated and characterized for transporting microfluid by AC electro-osmosis (ACEO). (queensu.ca)
- To characterize a specific function of the brain, invasive means such as implantable cortical microelectrode arrays that directly detect the electrical field potentials/spikes from the somatomotor areas have been used, for example, to provide BCI control options for quadriplegic patients. (nextbigfuture.com)
- BDD microelectrode arrays (MEA) further decrease the intrinsically low background current of BDD, yielding electrodes capable of ultra-sensitive analyte measurements. (fraunhofer.org)
- The functional significance of differences in the balance of excitatory to inhibitory synapses was confirmed by the assessment of network activity using microelectrode arrays. (elsevier.com)
- These results suggest that high-content imaging and microelectrode arrays provide complementary approaches for quantitative assessment of synaptogenesis, which should provide a robust readout of toxicologic and pharmacologic effects on this critical neurodevelopmental event. (elsevier.com)
- High density microelectrode arrays (MEAs) provide extracellular recordings from thousands of closely spaced electrodes and with sub-millisecond resolution. (biomedcentral.com)
- The Center for Microelectrode Technology Electrode Service Center now has sufficient production capacity to sell our ceramic-based microelectrode arrays (MEAs) to anyone wishing to purchase them for use in any electrochemical or electrophysiological recording system. (ukycenmet.com)
- All ceramic microelectrode arrays (MEAs) are pretested with peroxide to verify performance and only those that pass our criteria are shipped. (ukycenmet.com)
Gold microelectrode2
- Cyclic voltammetry was applied as the characterization technique for the gold microelectrode surface properties. (archives-ouvertes.fr)
- A unique beads polishing system incorporated at the electrode system maintains the electrode in good working condition, free of interferences at the gold microelectrode, and ensures stable measurement. (analyticon.com)
Electrodes1
- A realistic neural network was used to simulate a region of neocortex to obtain extracellular LFPs from 'virtual micro-electrodes' and produce test data for comparison with multisite microelectrode recordings. (yale.edu)
Electrochemical2
- The possibility of using such needles as protruding microelectrodes able to penetrate individual living cells, and thus providing an access channel to electrochemical signals within the cells, motivates the systematic analysis of the influence of the relevant etching parameters on the needle shape. (vde-verlag.de)
- The MIFE system uses a stepper motor-driven micromanipulator to move, in a "square wave", four microelectrodes that measure the electrochemical potential of the ions at two positions in solution close to a tissue surface. (edu.au)
MEAs1
- These MEAs can be fabricated on various substrates with custom designs including electrically isolated individually addressable microelectrodes. (fraunhofer.org)
Recordings4
- We describe radiologic atlas-based targeting using computed tomography and magnetic resonance imaging, physiological localization using microelectrode recordings, and macrostimulation techniques. (universitypressscholarship.com)
- The SEC-03M is a switched mode single electrode voltage and current clamp amplifier module for recordings with sharp microelectrodes or suction (patch) pipettes. (npielectronic.com)
- In this work, we investigate spatiotemporal characteristics of SPW-Rs and how microelectrode size and distance influence SPW-R recordings using a biophysical model of hippocampus. (yale.edu)
- Background: In deep brain stimulation of the subthalamic nucleus (STN-DBS) for Parkinson's Disease (PD), often microelectrode recordings (MER) are used for STN identification. (utwente.nl)
Electrode1
- The electrode can be connected to a preamplifier with a microelectrode holder . (elproscan.com)
Potentials3
- The microelectrodes detect the action potentials fired as well as their propagation across the network. (axionbiosystems.com)
- Through simulations of field potentials across a high-density microelectrode array, we demonstrate the importance of finding the ideal spatial resolution for capturing SPW-Rs with great sensitivity. (yale.edu)
- ABSTRACTOBJECTIVE:To examine the efficacy of intracerebral recording of visual evoked potentials (VEPs) during posteroventral pallidotomy comparing macro- and microelectrode stimulation.MATERIALS AND METHODS:The optic tract was identified by intracerebral recording of VEPs in 16 patients. (deepdyve.com)
Sensors2
Voltammetric1
- The work proposed is to attempt new methods of solid-state voltammetric microelectrode fabrication to enable new sensor configurations and environmentally-relevant experiments. (darkenergybiosphere.org)
Array6
- This chapter details the current CiPA protocol for evaluating drug-induced changes in hSC-CM electrophysiology using microelectrode array (MEA) technology. (axionbiosystems.com)
- A floating metal microelectrode array for chronic implantation. (nih.gov)
- Her research includes development of neuron-based biosensors on a microelectrode array platform and exploring a holistic approach to optimize a learner's mental state in order to improve learning outcomes. (oakland.edu)
- Biomedical Sciences: Development of neuron-based biosensors on a microelectrode array platform. (oakland.edu)
- What is a microelectrode array (MEA)? (axionbiosystems.com)
- Recent advances in microelectrode array technology now permit a direct examination of the way populations of sensory neurons encode information about a limb's position in space. (utah.edu)
Carbon6
- In this study, N-pyrrole (Py), N-phenylpyrrole (PhPy), and 1[4-methoxyphenyl]-1H-pyrrole (MPhPy) homopolymers were synthesized electrochemically onto carbon fiber microelectrodes (CFMEs). (itu.edu.tr)
- Carbon fiber microelectrode, 10 μm x 100 μm (diam. (kationscientific.com)
- Carbon fiber microelectrode, 34 μm x 200 μm (diam. (kationscientific.com)
- Carbon disc stereo microelectrode, 2x10μm (no. of discs x disc diam. (kationscientific.com)
- View cart "BASI-MF-2007 Carbon Fiber Microelectrode - 11 µm (±2 µm) diameter" has been added to your cart. (palmsens.com)
- WARRANTY INFORMATION: All carbon fiber microelectrodes (SF1As) are tested for performance prior to shipping. (ukycenmet.com)
Electrophysiology1
- Historically, iridium alloys were sought after for fountain pen tips and components of cannons that suffered from significant wear, while modern uses include electrical contacts for spark plugs, microelectrodes for use in electrophysiology, and extremely resilient aircraft engine parts . (americanelements.com)
Oxygen2
- This has to be considered when conparing the oxygen reduction activity (measured by impedance spectroscopy on microelectrodes) of single-phase with two-phase films. (mpg.de)
- Sediment pore-water dissolved oxygen concentrations were measured using a clark-type oxygen microelectrode (Unisense, Denmark). (ucar.edu)
Geochemical2
- This includes microelectrode measurements, geochemical analyses as well as optical and mineralogical analyses of temporal and spatial distribution of Fe(III) mineral formation. (uni-tuebingen.de)
- My interests cover a wide range of areas including redox reactions in the environment, trace element speciation in marine waters and sediments including metal-ligand complexes, biogeochemical processes in marine environments, application of molecular orbital theory to geochemical processes, in situ electrochemistry and microelectrode technology. (udel.edu)
Stimulation1
- Effects of localized stimulation by means of microelectrodes of the cardioinhibitory vagal center in Rana esculenta]. (cngb.org)
Spikes1
- As she pictured moving the cursor left and right, forward and backward, the microelectrodes picked up electrical "spikes" in her neurons. (nautil.us)
20201
- Se estima que para el año 2020 la producción de equipos eléctricos y electrónicos en el país alcanzará los $USD76,540 millones de dólares americanos (INEGI, 2012). (tec.mx)
Neurons1
- Kostyuk was the first Soviet scientist to use microelectrodes for intracellular recording of electrical signals in neurons. (shevchenko.org)
Technology1
- This paper describes the realization of Pt-tip microelectrodes by using microfabrication technology. (rero.ch)
Fabrication1
- In microfluidic, a fabrication of it devices with integrated microchannels and microelectrodes of dimensions are made comparable to biological cells or particles size. (intechopen.com)
Signals1
- The recording of neural signals with microelectrodes that are implanted into the cortex of the brain is potentially useful for a range of clinical applications. (cambridge.org)
Responses1
- To-date, most of the knowledge about SPW-Rs comes from experimental studies averaging responses from neuronal populations monitored by conventional microelectrodes. (yale.edu)
Electrical1
- By attaching microelectrodes to the insects' antennae, the researchers could measure the electrical impulses that are generated when mosquitoes recognize a chemical. (janetterallison.com)
Technique2
- The new technique relies on measuring 2 parameters simultaneously and at the same point in the water above the sediment: the fluctuating vertical velocity using an acoustic Doppler velocimeter and the fluctuating O 2 concentration using an O 2 microelectrode. (int-res.com)
- The ion-selective microelectrode technique to measure specific ion fluxes non-invasively is ideally suited to this purpose. (edu.au)
System1
- The system will also function as an excellent electrometer/recorder with a 10 Hz bandwidth for microelectrode studies of membrane potential or for any other data acquisition. (edu.au)
Studies1
- To test this hypothesis, 2D and 3D microelectrodes with different sizes were designed and fabricated for ac-EHD studies using standard lithography and etching processes. (edu.sa)
Combination1
- The microelectrodes were manufactured on PI by a combination of soft lithographical tools. (archives-ouvertes.fr)
Data1
- Microelectrode and respiration data also demonstrated a clear effect of organic loading on sediments. (edu.au)
Small2
- We most commonly perform ablation therapy by guiding a small needle and microelectrode to the source of the pain. (uthscsa.edu)
- It can be shown that the net flux of an ion, typically measured in units of nmol m -2 s -1 , may be found from a measurement of the change in voltage of an ion selective microelectrode that is moved through a small known distance in the solution. (edu.au)