Abstract:
:Phasic and tonic motor neurons of crustaceans differ strikingly in their junctional synaptic physiology. Tonic neurons generally produce small excitatory postsynaptic potentials (EPSPs) that facilitate strongly as stimulation frequency is increased, and normally show no synaptic depression. In contrast, phasic neurons produce relatively large EPSPs with weak frequency facilitation and pronounced depression. We addressed the hypothesis that mitochondrial function is an important determinant of the features of synaptic transmission in these neurons. Mitochondrial fluorescence was measured with confocal microscopy in phasic and tonic axons and terminals of abdominal and leg muscles after exposure to supravital mitochondrial fluorochromes, rhodamine-123 (Rh123) and 4-diethylaminostyryl-N-methylpyridinium iodide (4-Di-2-Asp). Mitochondria of tonic axons and neuromuscular junctions had significantly higher mean Rh123 and 4-Di-2-Asp fluorescence than in phasic neurons, indicating more accumulation of the fluorochromes. Mitochondrial membrane potential, which is responsible for Rh123 uptake and is related to mitochondrial oxidative activity (the production of ATP by oxidation of metabolic substrates), is likely higher in tonic axons. Electron microscopy showed that tonic axons contain approximately fivefold more mitochondria per microm2 cross-sectional area than phasic axons. Neuromuscular junctions of tonic axons also have a much higher mitochondrial content than those of phasic axons. We tested the hypothesis that synaptic fatigue resistance is dependent on mitochondrial function in crayfish motor axons. Impairment of mitochondrial function by uncouplers of oxidative phosphorylation, dinitrophenol or carbonyl cyanide m-chlorophenylhydrazone, or by the electron transport inhibitor sodium azide, led to marked synaptic depression of a tonic axon and accelerated depression of a phasic axon during maintained stimulation. Iodoacetate, an inhibitor of glycolysis, and chloramphenicol, a mitochondrial protein synthesis inhibitor, had no significant effects on either mitochondrial fluorescence or synaptic depression in tonic or phasic axons. Collectively, the results provide evidence that mitochondrial oxidative metabolism is important for sustaining synaptic transmission during maintained stimulation of tonic and phasic motor neurons. Tonic neurons have a higher mitochondrial content and greater oxidative activity; these features are correlated with their greater resistance to synaptic depression. Conversely, phasic neurons have a lower mitochondrial content, less oxidative activity, and greater synaptic fatigability.
journal_name
J Neurophysioljournal_title
Journal of neurophysiologyauthors
Nguyen PV,Marin L,Atwood HLdoi
10.1152/jn.1997.78.1.281subject
Has Abstractpub_date
1997-07-01 00:00:00pages
281-94issue
1eissn
0022-3077issn
1522-1598journal_volume
78pub_type
杂志文章abstract::Primate head-free saccade generator implements a desired (post-VOR) eye position command by anticipating intended head motion. J. Neurophysiol. 78: 2811-2816, 1997. When we glance between objects, the brain ultimately controls gaze direction in space. However, it is currently unclear how this is allocated into separat...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1997.78.5.2811
更新日期:1997-11-01 00:00:00
abstract::There is a great need to develop new approaches for rehabilitation of the upper limb after stroke. Robotic therapy is a promising form of neurorehabilitation that can be delivered in higher doses than conventional therapy. Here we sought to determine whether the reported effects of robotic therapy, which have been bas...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00336.2015
更新日期:2015-09-01 00:00:00
abstract::1. In the intact pond snail Planorbis corneus, a rapid tilt in any plane evoked a defense reaction consisting of a fast movement of the shell towards the head, shortening of the foot, inhibition of locomotion and of rhythmical feeding movements. This reaction was similar to the first phase of the general defense react...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1994.71.3.898
更新日期:1994-03-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1995.73.4.1600
更新日期:1995-04-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00698.2001
更新日期:2002-12-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.2000.84.1.472
更新日期:2000-07-01 00:00:00
abstract::1. It has been suggested that passive diffusion is the principal mechanism of the clearance of locally elevated extracellular potassium, K+o, in the cerebral cortex. This concept was based on the assumption that elevated K+ could be modeled as a point source. In the present study, the functional role of passive diffus...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1977.40.5.1015
更新日期:1977-09-01 00:00:00
abstract::1. This study demonstrates plasticity of the vestibuloocular reflex (VOR) in chickens and compares it to that of other species and to that of newly hatched chicks. Adaptive changes in the VOR were induced by subjecting the animals to combinations of visual and vestibular stimuli that simulated the effect of the VOR be...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1982.48.4.952
更新日期:1982-10-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00112.2020
更新日期:2020-05-01 00:00:00
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pub_type: 杂志文章
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更新日期:2010-09-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
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更新日期:2015-01-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1993.69.5.1784
更新日期:1993-05-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00862.2017
更新日期:2018-08-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1997.77.2.782
更新日期:1997-02-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.2001.85.4.1782
更新日期:2001-04-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00476.2016
更新日期:2017-02-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00657.2013
更新日期:2014-09-15 00:00:00
abstract::Nicotine evokes pain in the skin and oral mucosa and excites a subpopulation of cutaneous nociceptors, but little is known about the central transmission of chemogenic pain. We have investigated the responses of lumbar spinal wide dynamic range (WDR)-type dorsal horn neurons to intracutaneous (ic) microinjection of ni...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1999.82.6.3046
更新日期:1999-12-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1996.76.3.2005
更新日期:1996-09-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
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更新日期:2007-04-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00839.2005
更新日期:2006-04-01 00:00:00
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journal_title:Journal of neurophysiology
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更新日期:2013-08-01 00:00:00
abstract::Contact-evoked changes in EMG activity during human grasp. 2215 Cutaneous receptors in the digits discharge bursts of activity on contact with an object during human grasp. In this study, we investigated the contribution of this sensory activity to the responses of muscles involved in the task. Twelve subjects perform...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
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更新日期:1999-05-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00645.2003
更新日期:2003-11-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00841.2006
更新日期:2007-05-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1988.60.2.769
更新日期:1988-08-01 00:00:00
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journal_title:Journal of neurophysiology
pub_type: 杂志文章
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更新日期:2010-12-01 00:00:00
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journal_title:Journal of neurophysiology
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更新日期:2010-03-01 00:00:00
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pub_type: 杂志文章
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更新日期:2003-02-01 00:00:00
abstract::1. High-threshold Ca2+ currents were studied in large pyramidal cells acutely dissociated from the rat amygdaloid complex. L-, N-, and P-type currents were present in about equal proportions in these cells and accounted for most of the whole-cell current. ...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1994.71.1.433
更新日期:1994-01-01 00:00:00