Synaptic interactions between mammalian central neurons in cell culture. II. Quantal Analysis of EPSPs

The presynaptic release mechanism involved in excitatory synaptic connections between neurons in cell cultures of fetal mouse spinal cord were studied by statistical analysis of intracellularly recorded postsynaptic responses. Quantal parameters were determined for the EPSPs evoked in spinal cord (SC) neurons by stimulation of either other SC or dorsal root ganglion (DRG) neurons. Transmitter release was manipulated by varying the Ca2+ and Mg2+ content of the culture medium. The release process was represented better by binomial than by Poisson statistics. A method was derived for obtaining the probability of release and the number of release elements. The quantal content and the number of release elements were substantially higher for the SC-SC connection than for the DRG-SC connection. This was partially compensated for by a larger quantal amplitude for the DRG-SC connection. There was some indication that the probability of release was higher for the SC-SC connection. The relationship between transmitter output and effective external Ca2+ ion concentration was approximately linear.

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Synaptic interactions between mammalian central neurons in cell culture. III. Morphophysiological correlates of quantal synaptic transmission

Journal of Neurophysiology ◽

10.1152/jn.1983.49.6.1459 ◽

1983 ◽

Vol 49 (6) ◽

pp. 1459-1468 ◽

Cited By ~ 31

Author(s):

E. A. Neale ◽

P. G. Nelson ◽

R. L. Macdonald ◽

C. N. Christian ◽

L. M. Bowers

Keyword(s):

Spinal Cord ◽

Cell Culture ◽

Synaptic Transmission ◽

Synaptic Connection ◽

Fetal Mouse ◽

Mouse Spinal Cord ◽

Central Neurons ◽

Synaptic Interactions ◽

Anatomical Extent ◽

Rate Limiting

The statistical properties of excitatory synaptic transmission between neurons in cell cultures of fetal mouse spinal cord were studied and the anatomical extent of these connections demonstrated by horseradish peroxidase (HRP) injection of the presynaptic cell. In conjunction with previous experiments (7), we have correlated the number of boutons involved in a given synaptic connection with the physiologically determined number of release elements. The number of boutons is somewhat greater than the number of release elements, and our results are supportive of the conclusion of others (1, 2) that the physiologically defined release element corresponds to the bouton. We interpret this to suggest that a rate-limiting mechanism may operate at the level of the bouton to allow release of no more than one quantal unit of transmitter with each presynaptic action potential.

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Calcium currents and transmitter output in cultured spinal cord and dorsal root ganglion neurons

Journal of Neurophysiology ◽

10.1152/jn.1986.56.5.1257 ◽

1986 ◽

Vol 56 (5) ◽

pp. 1257-1267 ◽

Cited By ~ 17

Author(s):

M. Jia ◽

P. G. Nelson

Keyword(s):

Spinal Cord ◽

Dorsal Root Ganglion ◽

Dorsal Root ◽

Calcium Currents ◽

Dorsal Root Ganglion Neurons ◽

Ion Concentration ◽

Drg Neurons ◽

Voltage Dependent ◽

Ganglion Neurons

The effects of repetitive activation upon voltage-dependent calcium currents (ICa) and transmitter release were studied in dissociated cell cultures of fetal mouse spinal cord and dorsal root ganglion. Sodium and potassium currents were suppressed with tetrodotoxin (TTX) and tetraethylammonium (TEA) ions, 4-aminopyridine (4-AP), and cesium sulfate. Calcium currents were compared under voltage clamp before and after a series of depolarizing clamp pulses in spinal cord (SC) and dorsal root ganglion (DRG) neurons. Repetitive activation resulted in an exponential decline in ICa, with the decrease in ICa being much more marked in DRG compared with SC neurons. Both voltage-dependent inactivation and inactivation related to the intracellular movement of Ca2+ appeared to be involved in the decrement in ICa with repetitive activation. A decrease in transmitter output occurred with repetitive activation in DRG neurons but not in SC neurons (either excitatory or inhibitory). DRG neuron synaptic boutons had fewer mitochondria than did the boutons of either excitatory or inhibitory of SC neurons. The decrement in both ICa and synaptic transmitter output in DRG neurons could last for prolonged periods (at least minutes) following repetitive activation. We hypothesize that this vulnerability of DRG neurons to repetitive activation may be related, at least in part, to a relative incapacity to maintain a low intracellular calcium ion concentration [Ca]i during periods of increased calcium ingress associated with excitation. Such an incapacity to buffer [Ca]i may be one mechanism leading to the inactive synapses seen in some studies in vitro and in vivo of synaptic transmission.

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Faculty Opinions recommendation of The relationship between bladder management and health-related quality of life in patients with spinal cord injury in the UK.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.3414957.3109055 ◽

2010 ◽

Author(s):

Jean-Jacques Wyndaele

Keyword(s):

Quality Of Life ◽

Spinal Cord ◽

Health Related Quality ◽

Cord Injury ◽

Related Quality ◽

Health Related ◽

Bladder Management ◽

The Uk ◽

The Relationship

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Faculty Opinions recommendation of Thermal stability of lysozyme as a function of ion concentration: a reappraisal of the relationship between the Hofmeister series and protein stability.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.718160843.793500078 ◽

2014 ◽

Author(s):

Patricia C Weber

Keyword(s):

Thermal Stability ◽

Protein Stability ◽

Ion Concentration ◽

Hofmeister Series ◽

The Relationship ◽

Thermal Stability Of

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Faculty Opinions recommendation of Calcineurin Dysregulation Underlies Spinal Cord Injury-Induced K+ Channel Dysfunction in DRG Neurons.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.727847940.793536377 ◽

2017 ◽

Author(s):

James Trimmer

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

K Channel ◽

Drg Neurons ◽

Cord Injury

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Research on the Ignition Height and Reaction Flame Temperature of PTFE/Al/Si/CuO with Different Mass Ratios of PTFE/Si

Materials ◽

10.3390/ma14133464 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3464

Author(s):

Xuan Zou ◽

Jingyuan Zhou ◽

Xianwen Ran ◽

Yiting Wu ◽

Ping Liu ◽

...

Keyword(s):

Energy Release ◽

High Speed ◽

Flame Temperature ◽

Sintering Process ◽

Release Process ◽

Reactive Material ◽

Temperature Changes ◽

Release Capacity ◽

Mass Ratios ◽

The Relationship

Recent studies have shown that the energy release capacity of Polytetrafluoroethylene (PTFE)/Al with Si, and CuO, respectively, is higher than that of PTFE/Al. PTFE/Al/Si/CuO reactive materials with four proportions of PTFE/Si were designed by the molding–sintering process to study the influence of different PTFE/Si mass ratios on energy release. A drop hammer was selected for igniting the specimens, and the high-speed camera and spectrometer systems were used to record the energy release process and the flame spectrum, respectively. The ignition height of the reactive material was obtained by fitting the relationship between the flame duration and the drop height. It was found that the ignition height of PTFE/Al/Si/CuO containing 20% PTFE/Si is 48.27 cm, which is the lowest compared to the ignition height of other Si/PTFE ratios of PTFE/Al/Si/CuO; the flame temperature was calculated from the flame spectrum. It was found that flame temperature changes little for the same reactive material at different drop heights. Compared with the flame temperature of PTFE/Al/Si/CuO with four mass ratios, it was found that the flame temperature of PTFE/Al/Si/CuO with 20% PTFE/Si is the highest, which is 2589 K. The results show that PTFE/Al/Si/CuO containing 20% PTFE/Si is easier to be ignited and has a stronger temperature destruction effect.

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