scholarly journals Optogenetic analysis of synaptic transmission in the central nervous system of the nematode Caenorhabditis elegans

2011 ◽  
Vol 2 (1) ◽  
Author(s):  
Theodore H. Lindsay ◽  
Tod R. Thiele ◽  
Shawn R. Lockery
1976 ◽  
Vol 4 (3) ◽  
pp. 199-202 ◽  
Author(s):  
T. A. Torda ◽  
P. W. Gage

Thiopentone and pentobarbitone reduce the time constant of decay of miniature end-plate currents when applied in anaesthetic concentrations to the neuromuscular junction. Such an effect at central synapses would lead to failure of synaptic transmission in the central nervous system and may reflect a common mode of action of many anaesthetic drugs.


1958 ◽  
Vol 192 (3) ◽  
pp. 447-452 ◽  
Author(s):  
Sadayuki F. Takagi ◽  
Yutaka Oomura

The effect of nicotine on synaptic transmission in the frog and cat spinal cord was studied. Both a regular wick electrode and a microelectrode of the Ling-Gerard type were used. The reflex activity of the bullfrog spinal cord is facilitated by 0.01% nicotine solution, but is depressed and abolished by 0.1% solution. In the cat, intravenous administration of 150 mg/kg fails to block reflex activity, but topical application does block. The intracellular potential, of both frog and cat motoneurones, shows no change in the synaptic potential after application of the drug, but the spike appears after a shorter synaptic delay and one or more additional spikes appear. When the synaptic delay becomes sufficiently short, however, all spikes suddenly disappear, leaving the still unchanged synaptic potential. Occasionally the synaptic delay is again increased just before the spike potentials disappear. The excitability of a frog motoneurone was measured, by a recording microelectrode, before and after nicotine application. The drug first increased and then decreases excitability. Epinephrine can restore a reflex discharge depressed or abolished by nicotine. It is concluded that high concentrations of nicotine block synaptic transmission in the central nervous system, acting on the cell body but not on the synaptic potential.


Physiology ◽  
1996 ◽  
Vol 11 (4) ◽  
pp. 161-166
Author(s):  
H Ohmori

Hair cells transduce mechanical information into electrical signal and, via afferent synapse, transmit it to the central nervous system (CNS). Hair cells receive cholinergic efferent innervation from the CNS, and a long-lasting membrane hyperpolarization is produced by activation of Ca2+-activated K+ channels. Acetylcholine may facilitate afferent synaptic transmission by suppressing K+ channels on the afferent nerve terminal.


2010 ◽  
Vol 38 (6) ◽  
pp. 1527-1530 ◽  
Author(s):  
Joel D. Richter

Synapses, points of contact between axons and dendrites, are conduits for the flow of information in the circuitry of the central nervous system. The strength of synaptic transmission reflects the interconnectedness of the axons and dendrites at synapses; synaptic strength in turn is modified by the frequency with which the synapses are stimulated. This modulation of synaptic strength, or synaptic plasticity, probably forms the cellular basis for learning and memory. RNA metabolism, particularly translational control at or near the synapse, is one process that controls long-lasting synaptic plasticity and, by extension, memory formation and consolidation. In the present paper, I review some salient features of translational control of synaptic plasticity.


2017 ◽  
Vol 58 (6) ◽  
pp. 881-886 ◽  
Author(s):  
Michiyo Suzuki ◽  
Yuya Hattori ◽  
Tetsuya Sakashita ◽  
Yuichiro Yokota ◽  
Yasuhiko Kobayashi ◽  
...  

Abstract Radiation may affect essential functions and behaviors such as locomotion, feeding, learning and memory. Although whole-body irradiation has been shown to reduce motility in the nematode Caenorhabditis elegans, the detailed mechanism responsible for this effect remains unknown. Targeted irradiation of the nerve ring responsible for sensory integration and information processing would allow us to determine whether the reduction of motility following whole-body irradiation reflects effects on the central nervous system or on the muscle cells themselves. We therefore addressed this issue using a collimating microbeam system. However, radiation targeting requires the animal to be immobilized, and previous studies have anesthetized animals to prevent their movement, thus making it impossible to assess their locomotion immediately after irradiation. We developed a method in which the animal was enclosed in a straight, microfluidic channel in a polydimethylsiloxane chip to inhibit free motion during irradiation, thus allowing locomotion to be observed immediately after irradiation. The head region (including the central nervous system), mid region around the intestine and uterus, and tail region were targeted independently. Each region was irradiated with 12 000 carbon ions (12C; 18.3 MeV/u; linear energy transfer = 106.4 keV/μm), corresponding to 500 Gy at a φ20 μm region. Motility was significantly decreased by whole-body irradiation, but not by irradiation of any of the individual regions, including the central nervous system. This suggests that radiation inhibits locomotion by a whole-body mechanism, potentially involving motoneurons and/or body-wall muscle cells, rather than affecting motor control via the central nervous system and the stimulation response.


2020 ◽  
Vol 18 (10) ◽  
pp. 936-965
Author(s):  
Xuechao Hao ◽  
Mengchan Ou ◽  
Donghang Zhang ◽  
Wenling Zhao ◽  
Yaoxin Yang ◽  
...  

General anesthetics are a class of drugs that target the central nervous system and are widely used for various medical procedures. General anesthetics produce many behavioral changes required for clinical intervention, including amnesia, hypnosis, analgesia, and immobility; while they may also induce side effects like respiration and cardiovascular depressions. Understanding the mechanism of general anesthesia is essential for the development of selective general anesthetics which can preserve wanted pharmacological actions and exclude the side effects and underlying neural toxicities. However, the exact mechanism of how general anesthetics work is still elusive. Various molecular targets have been identified as specific targets for general anesthetics. Among these molecular targets, ion channels are the most principal category, including ligand-gated ionotropic receptors like γ-aminobutyric acid, glutamate and acetylcholine receptors, voltage-gated ion channels like voltage-gated sodium channel, calcium channel and potassium channels, and some second massager coupled channels. For neural functions of the central nervous system, synaptic transmission is the main procedure for which information is transmitted between neurons through brain regions, and intact synaptic function is fundamentally important for almost all the nervous functions, including consciousness, memory, and cognition. Therefore, it is important to understand the effects of general anesthetics on synaptic transmission via modulations of specific ion channels and relevant molecular targets, which can lead to the development of safer general anesthetics with selective actions. The present review will summarize the effects of various general anesthetics on synaptic transmissions and plasticity.


The tracheal supply to the central nervous system of the locust has been revealed by staining with cobalt sulphide. Air that enters through the first pair of thoracic spiracles is carried first to the brain and then to the rest of the central nervous system. The air is expelled through the abdominal spiracles, so that there is a one-way circulation with diffusional exchange only in the blindly ending tracheae that enter the brain or ganglia. Once inside a ganglion, the tracheae branch profusely to end in a mass of fine tracheoles through which gaseous exchange takes place. The densest tracheation is in the neuropile areas, where the spacing between tracheoles is about 17 μm. In the optic lobes, where there is order to the synaptic arrangement of a neuropile, there is a matching orderliness of the tracheation. Cortical areas, which contain the cell bodies of neurons, have only a sparse tracheation. It may be concluded that it is the processes associated with synaptic transmission that require the most immediate access to the sites of gaseous exchange.


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