scholarly journals OTTO LOEWI: ONE HUNDRED YEARS OF CONFIRMATION OF CHEMICAL NEUROTRANSMISSION

2021 ◽  
pp. 135-139
Author(s):  
Albino García Sacristán
Keyword(s):  
Experimental Study ◽  
Nobel Prize ◽  
Chemical Substance ◽  
Nerve Fibers ◽  
Nerve Impulses ◽  
Chemical Theory

In 1921, Otto Loewi published an experimental study that gave rise to the birth of the chemical theory of nerve transmission, according to which, the nerve current causes, at the end of nerve fibers, the release of a chemical substance called a neurotransmitter. For his discoveries related to the chemical neurotransmission of nerve impulses, Loewi received the Nobel Prize in Physiology or Medicine in 1936.

Simulations of Synaptic Transmission Using Lattice Boltzmann Methods

2002 ◽  
Author(s):  
Mehrak Mahmoudi ◽  
Piroz Zamankhan ◽  
William Polashenski
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Theoretical Model ◽  
Lattice Boltzmann ◽  
Chemical Substance ◽  
Human Central Nervous System ◽  
Lattice Boltzmann Methods ◽  
Nerve Impulses ◽  
System A ◽  
The Central Nervous System

The nervous system remains one of the least understood biological structures due in large part to the enormous complexity of this organ. A theoretical model for the transfer of nerve impulses would be valuable for the analysis of various phenomena in the nervous system, which are difficult to study by experiments. The central nervous system is composed of more than 100 billion neurons, through which information is transmitted via nerve impulses. Nerve impulses are not immediately apparent since each impulse may be blocked during transmission, changed from a single impulse into repetitive impulse, or integrated with impulses from other neurons to form highly intricate patterns. In the human central nervous system, a neuron secretes a chemical substance called a neurotransmitter at the synapse, and this transmitter in turn acts on another neuron to cause excitation, inhibition, or some other modification of its sensitivity.

EXPERIMENTAL STUDY OF THE REGENERATION OF SYMPATHETIC NERVE FIBERS AFTER NERVE HOMOGRAFTING

1974 ◽  
Vol 54 (6) ◽  
pp. 671-675 ◽  
Author(s):  
YASUSUKE HIRASAWA ◽  
RYONOSUKE ODA ◽  
KATSUYA NAKATANI ◽  
YOSHIAKI NOJYO
Keyword(s):  
Experimental Study ◽  
Sympathetic Nerve ◽  
Nerve Fibers ◽  
Sympathetic Nerve Fibers

scholarly journals INHIBITION IN THE EYE OF LIMULUS

1956 ◽  
Vol 39 (5) ◽  
pp. 651-673 ◽  
Author(s):  
H K. Hartline ◽  
Henry G Wagner ◽  
Floyd Ratliff
Keyword(s):  
Optic Nerve ◽  
Nervous Activity ◽  
Nerve Fibers ◽  
Inhibitory Influence ◽  
Partial Recovery ◽  
Deep Minimum ◽  
Inhibitory Interaction ◽  
Nerve Impulses ◽  
Visual Contrast ◽  
Fixed Region

In the compound lateral eye of Limulus each ommatidium functions as a single receptor unit in the discharge of impulses in the optic nerve. Impulses originate in the eccentric cell of each ommatidium and are conducted in its axon, which runs without interruption through an extensive plexus of nerve fibers to become a fiber of the optic nerve. The plexus makes interconnections among the ommatidia, but its exact organization is not understood. The ability of an ommatidium to discharge impulses in the axon of its eccentric cell is reduced by illumination of other ommatidia in its neighborhood: the threshold to light is raised, the number of impulses discharged in response to a suprathreshold flash of light is diminished, and the frequency with which impulses are discharged during steady illumination is decreased. Also, the activity that can be elicited under certain conditions when an ommatidium is in darkness can be inhibited similarly. There is no evidence for the spread of excitatory influences in the eye of Limulus. The inhibitory influence exerted upon an ommatidium that is discharging impulses at a steady rate begins, shortly after the onset of the illumination on neighboring ommatidia, with a sudden deep minimum in the frequency of discharge. After partial recovery, the frequency is maintained at a depressed level until the illumination on the neighboring receptors is turned off, following which there is prompt, though not instantaneous recovery to the original frequency. The inhibition is exerted directly upon the sensitive structure within the ommatidium: it has been observed when the impulses were recorded by a microelectrode thrust into an ommatidium, as well as when they were recorded more proximally in single fibers dissected from the optic nerve. Receptor units of the eye often inhibit one another mutually. This has been observed by recording the activity of two optic nerve fibers simultaneously. The mediation of the inhibitory influence appears to depend upon the integrity of nervous interconnections in the plexus: cutting the lateral connections to an ommatidium abolishes the inhibition exerted upon it. The nature of the influence that is mediated by the plexus and the mechanism whereby it exerts its inhibitory action on the receptor units are not known. The depression of the frequency of the discharge of nerve impulses from an ommatidium increases approximately linearly with the logarithm of the intensity of illumination on receptors in its vicinity. Inhibition of the discharge from an ommatidium is greater the larger the area of the eye illuminated in its vicinity. However, equal increments of area become less effective as the total area is increased. The response of an ommatidium is most effectively inhibited by the illumination of ommatidia that are close to it; the effectiveness diminishes with increasing distance, but may extend for several millimeters. Illumination of a fixed region of the eye at constant intensity produces a depression of the frequency of discharge of impulses from a nearby ommatidium that is approximately constant, irrespective of the level of excitation of the ommatidium. The inhibitory interaction in the eye of Limulus is an integrative process that is important in determining the patterns of nervous activity in the visual system. It is analogous to the inhibitory component of the interaction that takes place in the vertebrate retina. Inhibitory interaction results in the exaggeration of differences in sensory activity from different regions of the eye illuminated at different intensities, thus enhancing visual contrast.

scholarly journals Electrophysiology of the Insect Dorsal Ocellus

1961 ◽  
Vol 44 (3) ◽  
pp. 605-627 ◽  
Author(s):  
Philip Ruck
Keyword(s):  
Cell Layer ◽  
Receptor Cell ◽  
Photoreceptor Cells ◽  
Nerve Fibers ◽  
Spontaneous Discharge ◽  
Generator Potential ◽  
Nerve Impulses ◽  
Potential Component ◽  
Ocellar Nerve ◽  
State Component

Dorsal ocelli are small cup-like organs containing a layer of photoreceptor cells, the short axons of which synapse at the base of the cup with dendritic terminals of ocellar nerve fibers. The ocellar ERG of dragonflies, recorded from the surface of the receptor cell layer and from the long lateral ocellar nerve, contains four components. Component 1 is a depolarizing sensory generator potential which originates in the distal ends of the receptor cells and evokes component 2. Component 2 is believed to be a depolarizing response of the receptor axons. It evokes a hyperpolarizing postsynaptic potential, component 3, which originates in the dendritic terminals of the ocellar nerve fibers. Ocellar nerve fibers in dragonflies are spontaneously active, discharging afferent nerve impulses (component 4) in the dark-adapted state. Component 3 inhibits this discharge. The ERG of the cockroach ocellus is similar. The main differences are that component 3 is not as conspicuous as in the dragonflies and that in most cases ocellar nerve impulses appear only as a brief burst at "off." In one preparation a spontaneous discharge of nerve impulses was observed. As in the dragonflies, this was inhibited by illumination.

scholarly journals Delay-induced destabilization of entrainment of nerve impulses on ephaptically coupled nerve fibers

2009 ◽  
Vol 79 (1) ◽  
Author(s):  
Mohit H. Adhikari ◽  
John K. McIver ◽  
Evangelos A. Coutsias
Keyword(s):  
Nerve Fibers ◽  
Nerve Impulses

scholarly journals EFEKTIVITAS PIJAT PUNGGUNG TERHADAP INTENSITAS NYERI REMATIK SEDANG PADA WANITA LANJUT USIA DI DESA KARYAWANGI KABUPATEN BANDUNG BARAT

2017 ◽  
Vol 3 (1) ◽  
pp. 53
Author(s):  
Pera Siahaan ◽  
Nurhayati Siagian ◽  
Yunus Elon
Keyword(s):  
Rheumatoid Arthritis ◽  
Experimental Study ◽  
Sensory Nerve ◽  
Pain Scale ◽  
Nerve Fibers ◽  
Young Age ◽  
Rheumatic Pain ◽  
Joint Problem ◽  
Before And After ◽  
Back Massage

ABSTRAK Pendahuluan: Rematik merupakan masalah persendian yang menimbulkan rasa nyeri baik wanita maupun laki-laki dan sering terjadi pada orang tua dibandingkan pada usia muda. Penanganan yang tepat untuk menangani rematik secara nonfarmakologis salah satunya adalah pijat punggung. Pijat punggung dapat menurunkan rasa nyeri, hal ini disebabkan pijat punggung menghasilkan pelepasan endorphin serta menstimulasi serabut saraf sensorik delta –A dan serabut C sehingga menurunkan impuls nyeri. Penelitian ini dilakukan untuk mengetahui efektifitas pijat punggung terhadap intensitas skala nyeri sedang pada wanita lanjut usia di Desa Karyawangi Kabupaten Bandung Barat. Penelitian ini merupakan penelitian eksperimen dengan one group pretest-posttest designt. Subjek dalam penelitian ini sebanyak 17 orang sesuai dengan kriteria penelitian. Tingkat nyeri rematik menggunakan Rheumatoid Arthritis Pain Scale (RAPS). Perolehan data nyeri rematik sebelum dan sesudah pemberian intervensi dihitung menggunakan rumus mean. Kemudian dilanjutkan dengan uji statistik melaui uji-t sampel paired. Hasil uji statistik pada pijat punggung menunjukkan bahwa thitung (8,641) > ttabel (2,120) dengan taraf kepercayaan 95% α = 0,05 yang berarti bahwa Ho yang menyatakan tidak ada perbedaan pemberian pijat punggung pada wanita lanjut usia di Desa Karyawangi Kabupaten Bandung Barat di tolak. Kesimpulan dari penelitian ini adalah terdapat penurunan yang signifikan terhadap penurunan skala nyeri rematik pada wanita lanjut usia di Desa Karyawangi Kabupaten Bandung Barat. Diskusi: Pemberian intervensi pijat punggung selama dua hari dapat menurunkan skala nyeri sedang rematik.   Kata Kunci: Nyeri Rematik, Pijat Punggung   ABSTRACT Introduction: Rheumatism is a joint problem that it was happen in both women and men also often going on old man than at a young age. The best proper handling to handle rheumatism in nonfarmakologi in one exception is backing massage. Back massage can reduce pain this is because back massage produce to release of endorphin and stimulate sensory nerve fibers-A delta and fibers C thus reducing pain impulses. This study was conducted to know the effectiveness of back massage to scale the intensity of pain was in women aged in Karyawangi Village West Bandung. This study was an experimental study with one group pretest and postest design. Subjects of this study were 17 in accordance with the criteria. The level of rheumatism pain data before and after intervention administration was calculated using mean formula and continued with statistic test through paired test-t sample. The result of statistic test of back massage was showed that tcount (8,642) > ttable (2,120) with level of confidence 95 % α = 0,05 it mean that Ho there is no significance different administration in back massage for elder women in Karyawangi Village West Bandung Rejected. The conclusion from the study there was decrease in scale a rheumatic pain in women aged in Karyawangi Village West Bandung. Discussion: The gived of intervention is backing massage can reduce pain often. Keywords: Rheumatic pain, Back Massage

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