scholarly journals Heterologous acclimation: a novel approach to the study of thermal acclimation in the crab Cancer pagurus

1999 ◽  
Vol 277 (1) ◽  
pp. R24-R30 ◽  
Author(s):  
Timothy Pearson ◽  
David Hyde ◽  
Ken Bowler
Keyword(s):  
Central Nervous System ◽  
Tissue Temperature ◽  
Resting Potential ◽  
Acclimation Temperature ◽  
Cancer Pagurus ◽  
Novel Approach ◽  
Excitatory Junction Potential ◽  
Leg Muscle ◽  
Temperature Constant ◽  
Junction Potential

The control of the attainment of acclimation in Cancer pagurus has been studied. Homologous (8 or 22°C) and heterologous acclimation [central nervous system (CNS) and periphery of crabs simultaneously held at 8 or 22°C] were used. The dependence of electrophysiological parameters of dactylopodite closer muscles of walking legs on nerve stimulation was determined between 6 and 26°C. Muscle resting potential (RP) hyperpolarized linearly with increasing measurement temperatures and showed a 69% compensation between 8 and 22°C on homologous acclimation. With the CNS temperature constant at 8°C, the leg muscle RP showed a 72% compensation on heterologous acclimation to 8 and 22°C; when CNS temperature was constant at 22°C, leg muscle RP showed a 48% compensation on heterologous acclimation to 8 and 22°C. In homologous acclimation, the shape of the excitatory junction potential vs. temperature relationship was characteristic of acclimation temperature. In heterologous acclimation, the shape of this plot was related to the temperature experienced by the leg and not by the CNS. Thus acclimation was principally dependent on local tissue temperature and was relatively independent of CNS or hormonal influences.

Electrophysiological Investigations of the Heart of Squilla Mantis

1964 ◽  
Vol 41 (4) ◽  
pp. 701-722
Author(s):  
HILARY F. BROWN
Keyword(s):  
Heart Muscle ◽  
Vital Staining ◽  
Heart Beat ◽  
Nerve Endings ◽  
Resting Potential ◽  
Muscle Membrane ◽  
Absolute Level ◽  
Local Contraction ◽  
Set Up ◽  
Junction Potential

1. The histology of the heart muscle of Squilla mantis is briefly described. Vital staining with methylene blue revealed only a sparse distribution of nerve endings on the muscle network. 2. Intracellular electrodes recorded from the muscle a multi-peaked junction potential at each heart beat. Each peak followed an impulse in the ganglionic nerve trunk burst. All the peaks were approximately the same height and none more than about three-fifths the height of the resting potential (average values for 10 hearts: resting potential, 51.5 mV; junction potential, 27.6 mV). 3. Inverted (negative-going) signals were never recorded just outside the muscle membrane suggesting that at all the points which were searched the membrane was acting passively. 4. Driving Squilla heart muscle via its nerve supply at 100 stimuli per second did not depolarize it by more than about 35 mV, nor would depolarizing pulses given directly to a fibre through an intracellular electrode set up any sort of current-generating activity in the membrane. 5. The magnitude of muscle contraction, measured locally using a microelectrode transducer, depended on the absolute level of the potential across the membrane, rather than on change of potential. 6. A directly applied electrotonus, similar in magnitude and duration to the nerve-induced junction potential, caused a local contraction of similar magnitude. 7. The recorded junction potential is therefore interpreted as the composite record of the electrotonus spreading within the muscle network from current initiated at relatively infrequent active points on the muscle membrane (the nerve endings) which passively depolarizes the rest of the membrane. 8. The junction potentials showed facilitation when the intervals between them were below 4 sec. At intervals less than 630 msec, they summed.

Effects of a thioreactive agent, diamide, on neuromuscular transmission in lobster

1982 ◽  
Vol 242 (1) ◽  
pp. C59-C64 ◽  
Author(s):  
C. A. Colton ◽  
J. S. Colton
Keyword(s):  
Transmitter Release ◽  
Neuromuscular Transmission ◽  
Similar Response ◽  
Free Solution ◽  
Frequency Increase ◽  
Short Term ◽  
Excitatory Junction Potential ◽  
Sites Of Action ◽  
Potential Frequency ◽  
Junction Potential

Diamide[diazine-dicarboxylic acid-bis(dimethylamide)], a thiol-oxidizing agent, has both pre- and postsynaptic actions on the glutaminergic neuromuscular junction of the lobster walking leg. Postsynaptically, diamide produced an increase in the response to exogenously applied glutamate, whereas the effect of diamide on presynaptic transmitter release involved two major changes: 1) a decrease in excitatory junction potential amplitude and 2) an increase in miniature junction potential frequency. Short-term facilitation also decreased. Equilibration with 1,4-dithiothreitol (a sulfhydryl-reducing agent) reversed the decline in excitatory junction potential frequency, and the fall in short-term facilitation. The miniature junction potential frequency increase induced by diamide was independent of external Ca2+, as diamide in a Ca2+-free solution produced a similar response to that in a Ca2+-containing solution. We propose that the action of diamide on transmitter release is similar to the action of polyvalent cations, i.e., diamide has two sites of action, a blockade of inward Ca2+ flux and an increased release of Ca2+ inside the terminal.

scholarly journals Native Separation and Metallation Analysis of SOD1 Protein from the Human Central Nervous System: A Methodological Workflow

2020 ◽  
Author(s):  
Stéphane Roudeau ◽  
Benjamin G. Trist ◽  
Asuncion Carmona ◽  
Katherine M. Davies ◽  
Glenda M. Halliday ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
High Sensitivity ◽  
Size Exclusion ◽  
Spinal Cord Tissue ◽  
Human Tissues ◽  
Human Central Nervous System ◽  
Copper Zinc Superoxide Dismutase ◽  
Novel Approach ◽  
Exclusion Chromatography

We developed a methodological workflow combining size exclusion chromatography, native isoelectric focusing, and high sensitivity X-ray-based metal detection within electrophoresis gels to analyze the metal content of single proteins purified from minimal amounts (<20 mg) of post-mortem human brain and spinal cord tissue. An important metalloprotein in the human central nervous system is copper-zinc superoxide dismutase (SOD1), an antioxidant enzyme linked to the aetiology of both amyotrophic lateral sclerosis and Parkinson’s disease. Abnormal SOD1 metallation is suspected to play a role in the pathogenic aggregation of SOD1 in both disorders, although data describing SOD1 metal occupancy in human tissues has not previously been reported. Validating our novel approach we demonstrated step-by-step metal preservation, preserved SOD1 activity, and substantial enrichment of SOD1 protein vs confounding metalloproteins. We found Cu and Zn were bound to SOD1 in a ratio of 1.12 ± 0.28 in human central nervous system tissues from healthy individuals, a ratio close to the expected value of 1. Our methodological workflow can be adapted to study a range of metalloproteins from human tissues and other sources.<br>

Dye-enhanced Ablation of Enamel by Pulsed Lasers

1994 ◽  
Vol 73 (12) ◽  
pp. 1841-1847 ◽  
Author(s):  
E. Jennett ◽  
M. Motamedi ◽  
S. Rastegar ◽  
C. Frederickson ◽  
C. Arcoria ◽  
...  
Keyword(s):  
Laser Action ◽  
Knoop Hardness ◽  
Tissue Temperature ◽  
Surrounding Tissue ◽  
Hard Tissue ◽  
Nd:Yag Lasers ◽  
Dental Hard Tissue ◽  
India Ink ◽  
Novel Approach ◽  
Laser Induced Damage

Laser removal of dental hard tissue has been proposed as a replacement for or augmented approach to the dental handpiece. The main limitation for widespread usage of lasers in dentistry has been inefficient ablation of dental hard tissue, accompanied by potential laser-induced damage to the surrounding tissue. The research focuses on a novel approach for enhancement of tissue ablation and confinement of laser interaction to a small tissue volume by controlled placement of an exogenous dye on the enamel surface. Studies were done with both pulsed alexandrite and pulsed Nd:YAG lasers, with indocyanine green and India ink, respectively, used as photo-absorbers. These dye-enhanced laser processes demonstrated the feasibility of this technique for cavity preparation. While control studies produced little or no appreciable crater, average preparation depth for the dye-enhanced ablation was from 1 to 1.5 mm, with a diameter of approximately 0.6 mm. Knoop hardness measurements show that, surrounding the crater, there is a small annular region slightly softened by the laser action. SEM studies of the interior structure of the tooth did not show significant damage to the surrounding tissue. Temperature measurement studies indicated that the pulsed nature of the laser, combined with the photoabsorbing dye, effectively prevented significant temperature rise at the pulp. The remarkable effectiveness of this technique in creating cavity preparations and the absence of any notable collateral damage to the surrounding tissue suggest that dye-enhanced pulsed-laser ablation could be used as an alternative to the dental handpiece in selected procedures.

Role of Immune Cells in the Course of Central Nervous System Injury: Modulation with Natural Products

2016 ◽  
Vol 22 (6) ◽  
pp. 701-708 ◽  
Author(s):  
Thea Magrone ◽  
Matteo Antonio Russo ◽  
Emilio Jirillo
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Immune Cells ◽  
Treg Cells ◽  
Host Immune System ◽  
Cns Injury ◽  
Omega 3 ◽  
Functional Activities ◽  
Novel Approach ◽  
The Central Nervous System

Immune cells actively participate to the central nervous system (CNS) injury either damaging or protecting neural tissue with release of various mediators. Residential microglia and monocyte-derived macrophages play a fundamental role within the injured CNS and, here, special emphasis will be placed on M1 and M2 macrophages for their different functional activities. On the other hand, peripheral T regulatory (Treg) cells exert antiinflammatory activities in the diseased host. In this respect, activation of Treg cells by nutraceuticals may represent a novel approach to treat neuroinflammation. Omega-3 fatty acids and polyphenols will be described as substances endowed with antioxidant and anti-inflammatory activities. However, taking into account that Treg cells act in the later phase of CNS injury, favoring immune suppression, manipulation of host immune system with both substances requires caution to avoid undesired side effects.

3 LOSS OF SEROTONIN-INDUCED EXCITATORY JUNCTION POTENTIAL AUTOMATICITY AT CRAYFISH WALKING LIMB OPENER MUSCLES

2005 ◽  
Vol 53 (2) ◽  
pp. S357.3-S357
Author(s):  
E. A. Goebel ◽  
Z. H. Dodd ◽  
A. Losiniecki ◽  
D. Hertzler ◽  
R. Hasan ◽  
...  
Keyword(s):  
Excitatory Junction Potential ◽  
Junction Potential
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