scholarly journals THE LOCUS OF THE ACTION OF VERATRIN

1924 ◽  
Vol 6 (5) ◽  
pp. 615-624 ◽  
Author(s):  
Charles L. Wible
Keyword(s):  
Sciatic Nerve ◽  
Small Groups ◽  
Peripheral Nerves ◽  
Gastrocnemius Muscle ◽  
Nerve Fibers ◽  
Sartorius Muscle ◽  
Direct Stimulation ◽  
Cerebral Ganglia ◽  
Two Stages ◽  
Stimulation Of

1. In Mnemiopsis veratrin shows two stages of veratrin poisoning. First, inhibition of the beats of the plates which disappears on cutting them away either singly or in small groups. Second, after half an hour mechanical stimulation excites the beat of the plates in the intact veratrinized animal. It is concluded that veratrin acts on nervous tissue and not on the substance of the swimming plates. 2. In Lumbricus, veratrin acts on the ventral nerve cord alone, and not on the muscles and peripheral nerves. 3. In Musca, veratrin first causes opisthotonos, then spasms and extreme flexion of the legs. Decapitation causes these effects to disappear hence veratrin acts on the cerebral ganglia of the fly. 4. Veratrin applied to the sciatic nerve of the frog causes, after a latent period of 20 minutes, irregular contractions of the gastrocnemius which persist for an hour or more. Veratrin is thus a neurophil alkaloid of the first class as well as second and in this way resembles tetraethyl ammonium chloride. 5. If the end of a sciatic nerve is dipped into veratrin solution, then direct stimulation of the gastrocnemius muscle results in contraction with delayed relaxation, although the muscle itself is not subject to the action of veratrin. 6. By means of preparations of the sartorius muscle of the frog it is shown that veratrin acts not on the muscle cells directly but on the nerve fibers. Hence veratrin produces the characteristic muscle curve showing delayed relaxation by its action on the nervous elements.

CONDUCTION BLOCK OF TERMINAL SOMATIC MOTOR FIBERS IN TICK PARALYSIS

1960 ◽  
Vol 38 (3) ◽  
pp. 287-295 ◽  
Author(s):  
Maurice F. Murnaghan
Keyword(s):  
Motor Nerve ◽  
Conduction Block ◽  
Nerve Impulse ◽  
Nerve Fibers ◽  
Treated Animal ◽  
Direct Stimulation ◽  
High Potassium ◽  
Control Value ◽  
Choline Acetylase ◽  
Stimulation Of

In the perfused anterior tibial muscle of the tick-paralyzed dog acetylcholine in excess of the control value is not liberated on stimulation of the peroneal nerve; in the normal muscle 7 μμg of acetylcholine is liberated per nerve volley. The paralysis is evidently not due to defective synthesis of acetylcholine because acetylcholine is liberated in control and high-potassium perfusates, the choline acetylase activity and the acetylcholine content of lumbar ventral roots and peroneal nerves do not differ from that in normal dogs, and the tick-paralyzed muscle differs from that in the hemicholinium-treated animal in its response to a train of nerve pulses after previous tetanization. As somatic motor nerve fibers in the paralyzed dog have previously been shown to conduct a nerve impulse and the factors required for acetylcholine release at the nerve terminal apparently are not absent in the paralyzed animal, the mechanism of the paralysis is probably due to an inability of the nerve impulse to traverse the terminal presynaptic fibers. The 'lesion' evidently extends to the end of the presynaptic fiber, i.e. more distally than in botulism, because direct stimulation of the tick-paralyzed muscle fails to liberate acetylcholine.

scholarly journals Combination of Acellular Nerve Graft and Schwann Cells-Like Cells for Rat Sciatic Nerve Regeneration

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Songtao Gao ◽  
Yan Zheng ◽  
Qiqing Cai ◽  
Zhansheng Deng ◽  
Weitao Yao ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Sciatic Nerve ◽  
Gastrocnemius Muscle ◽  
Nerve Fibers ◽  
Recovery Ratio ◽  
Myelinated Nerve ◽  
Myelinated Nerve Fibers ◽  
Nerve Grafts ◽  
Group A ◽  
Wet Weight

Objective.To investigate the effect of tissue engineering nerve on repair of rat sciatic nerve defect.Methods.Forty-five rats with defective sciatic nerve were randomly divided into three groups. Rats in group A were repaired by acellular nerve grafts only. Rats in group B were repaired by tissue engineering nerve. In group C, rats were repaired by autogenous nerve grafts. After six and twelve weeks, sciatic nerve functional index (SFI), neural electrophysiology (NEP), histological and transmission electron microscope observation, recovery ratio of wet weight of gastrocnemius muscle, regenerated myelinated nerve fibers number, nerve fiber diameter, and thickness of the myelin sheath were measured to assess the effect.Results.After six and twelve weeks, the recovery ratio of SFI and wet weight of gastrocnemius muscle, NEP, and the result of regenerated myelinated nerve fibers in groups B and C were superior to that of group A (P<0.05), and the difference between groups B and C was not statistically significant (P>0.05).Conclusion.The tissue engineering nerve composed of acellular allogenic nerve scaffold and Schwann cells-like cells can effectively repair the nerve defect in rats and its effect was similar to that of the autogenous nerve grafts.

scholarly journals Perspective Nerve Conduits for Stimulation of Regeneration of Damaged Peripheral Nerves

2018 ◽  
Vol 73 (6) ◽  
pp. 388-400
Author(s):  
Polina K. Miroshnikova ◽  
Alexey V. Lyundup ◽  
Nikolay P. Batsalenko ◽  
Mikhail E. Krasheninnikov ◽  
Yuanyuan Zhang ◽  
...  
Keyword(s):  
Peripheral Nerves ◽  
Severe Trauma ◽  
Nerve Fibers ◽  
Biologically Active ◽  
Active Components ◽  
Advantages And Disadvantages ◽  
Nerve Conduits ◽  
Golden Standard ◽  
Preclinical And Clinical Studies ◽  
Stimulation Of

Nerve damage is a common severe trauma caused by a complete or partial disruption of the integrity of the nerve trunk and appropriate dissociation of the CNS and denervated tissue. «Golden standard» in the treatment of extensive injuries of peripheral nerves is the use of autografts of nerve fibers, but when they are used, pathological disturbances appear in the donor zone and the results of surgical treatment are not always satisfactory. Currently, an alternative to the traditional method is the use of nerve conduits (conductors) for directed regeneration of axons. In this work, the results of the application of nerve conductors from various materials and with various biologically active components in preclinical and clinical studies, as well as conduits used in clinical practice, were analyzed. The efficiency of regeneration was compared, on the basis of the analysis the conductor most suitable for successful nerve regeneration was selected, including approaches for creating innervated tissue engineered constructs. In this work, we have collected research on nerve conductors from various materials with various prescribed properties using certain factors used to treat damage to the peripheral nervous system, showing all the advantages and disadvantages of their use, which makes it possible to develop and create a conduit that meets all the requirements of modern regenerative medicine.

scholarly journals ASCENT (Automated Simulations to Characterize Electrical Nerve Thresholds): A pipeline for sample-specific computational modeling of electrical stimulation of peripheral nerves

2021 ◽  
Vol 17 (9) ◽  
pp. e1009285
Author(s):  
Eric D. Musselman ◽  
Jake E. Cariello ◽  
Warren M. Grill ◽  
Nicole A. Pelot
Keyword(s):  
Electrical Stimulation ◽  
Computational Modeling ◽  
Peripheral Nerves ◽  
Nerve Fibers ◽  
Great Promise ◽  
Simulation Data ◽  
Stimulation Parameters ◽  
Neural Anatomy ◽  
Disease And Disorders ◽  
Stimulation Of

Electrical stimulation and block of peripheral nerves hold great promise for treatment of a range of disease and disorders, but promising results from preclinical studies often fail to translate to successful clinical therapies. Differences in neural anatomy across species require different electrodes and stimulation parameters to achieve equivalent nerve responses, and accounting for the consequences of these factors is difficult. We describe the implementation, validation, and application of a standardized, modular, and scalable computational modeling pipeline for biophysical simulations of electrical activation and block of nerve fibers within peripheral nerves. The ASCENT (Automated Simulations to Characterize Electrical Nerve Thresholds) pipeline provides a suite of built-in capabilities for user control over the entire workflow, including libraries for parts to assemble electrodes, electrical properties of biological materials, previously published fiber models, and common stimulation waveforms. We validated the accuracy of ASCENT calculations, verified usability in beta release, and provide several compelling examples of ASCENT-implemented models. ASCENT will enable the reproducibility of simulation data, and it will be used as a component of integrated simulations with other models (e.g., organ system models), to interpret experimental results, and to design experimental and clinical interventions for the advancement of peripheral nerve stimulation therapies.

Physiological effects of thermode and microwave stimulation of peripheral nerves

1962 ◽  
Vol 203 (2) ◽  
pp. 374-378 ◽  
Author(s):  
Robert D. McAfee
Keyword(s):  
Blood Pressure ◽  
Microwave Irradiation ◽  
Peripheral Nerve ◽  
Peripheral Nerves ◽  
Physiological Effect ◽  
Nerve Fibers ◽  
Physiological Effects ◽  
Vascular Responses ◽  
Total Body ◽  
Stimulation Of

Physiological effects produced in cats, dogs, rabbits, and rats by microwave irradiation (3-cm radar and 12.2-cm Microtherm) are duplicated in these animals by heating peripheral nerves with a warm-water or resistance-wire thermode. Identical effects occur when a temperature ranging between 45–47 C is attained by either of these means at a treated peripheral nerve or within tissue rich in peripheral nerve fibers. The response elicited by thermode or microwave stimulation includes arousal reactions, blood pressure and vascular responses, and signs of neurohumoral activity. We have demonstrated that the physiological effect of microwave radiation is a result of thermal stimulation of peripheral nerves which occurs independently of a significant increase in skin temperature or of total body heating.

Static muscular contraction elicits a pressor reflex in the chicken

1997 ◽  
Vol 272 (3) ◽  
pp. R759-R765 ◽  
Author(s):  
I. C. Solomon ◽  
T. P. Adamson
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Sciatic Nerve ◽  
Arterial Pressure ◽  
Gastrocnemius Muscle ◽  
Muscular Contraction ◽  
Arterial Blood ◽  
Static Contraction ◽  
Stimulation Of

Static muscular contraction has been shown to increase arterial blood pressure and heart rate in humans and other mammals. It is not clear, however, whether birds exhibit a similar response to this maneuver. Therefore, we designed these experiments to determine if the chicken exhibits a cardiovascular response to static muscular contraction and if the observed responses are evoked through a reflex involving muscle afferents. Static contraction of the gastrocnemius muscle was evoked by electrically stimulating the sciatic nerve at 1.5-3.0 times motor threshold (30-40 Hz; 0.025 ms) in 13 chloralose-anesthetized cockerels. We measured arterial blood pressure and muscle tension before and during static contraction and calculated mean arterial pressure and heart rate from the arterial pressure trace. We found that static contraction of the gastrocnemius muscle increased mean arterial pressure from 71 +/- 4 to 95 +/- 4 mmHg (P < 0.05) and increased heart rate from 304 +/- 8 to 345 +/- 10 beats/min (P < 0.05). Furthermore, we found that stimulation of the sciatic nerve after paralysis of the birds with vecuronium bromide or stimulation of the cut peripheral end of the sciatic nerve (using the same stimulation parameters described above) evoked no change in mean arterial pressure or heart rate. We conclude that static muscular contraction of the gastrocnemius muscle in the chicken elicits a pressor response and that this response is due to a reflex arising from the contracting muscles.

scholarly journals Fluorescence Changes in Nerve Induced by Stimulation

1962 ◽  
Vol 46 (2) ◽  
pp. 267-275 ◽  
Author(s):  
Georges Ungar ◽  
Dominick V. Romano
Keyword(s):  
Absorption Spectrum ◽  
Electrical Stimulation ◽  
Peripheral Nerves ◽  
Control Level ◽  
Nerve Fibers ◽  
Ultraviolet Absorption Spectrum ◽  
Structural Rearrangements ◽  
Tissue Extracts ◽  
Fluorescent Method ◽  
Stimulation Of

It was previously assumed, on the basis of changes in the ultraviolet absorption spectrum and of increase in ionizable sulfhydryl groups, that during excitation the proteins of excitable structures undergo some structural rearrangements, and these rearrangements may be similar to those designated by the term transconformation. In the present experiments, it was observed that electrical stimulation of peripheral nerves from rat, guinea pig, frog, and crab causes a decrease in their fluorescence. The peaks of the emission and activation spectra correspond to those attributed to proteins. Denaturing agents, such as urea, were also found to decrease the fluorescence of nerve extracts. It is, therefore, probable that the decrease in fluorescence, associated with the excited state, is due to a change in the configuration of the nerve proteins. The fluorescent method is applicable not only to tissue extracts but allows the observation of surviving nerve fibers before, during, and after stimulation. It showed that fluorescence of the fibers decreases invariably during stimulation and tends to return to the control level during restoration. The reduction in fluorescence is quantitatively related to the number of stimuli received by the nerve.

scholarly journals EFFICACY OF FIBRIN MATRIX WITH NEUROINDUCED MESENCHYMAL STEM CELLS TRANSPLANTATION FOR RESTORATION SCIATIC NERVE FUNCTION AFTER ITS COMPLETE RUPTURE IN RATS

2019 ◽  
Vol 6 (3) ◽  
Author(s):  
V. Pyatykop ◽  
V. Kaliuzhka ◽  
O. Shchegelska ◽  
M. Markevych
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Sciatic Nerve ◽  
Connective Tissue ◽  
Peripheral Nerves ◽  
Nerve Fibers ◽  
Nerve Function ◽  
Partial Restoration ◽  
Fibrin Matrix ◽  
Stem Cells Transplantation

Abstract EFFICACY OF FIBRIN MATRIX WITH NEUROINDUCED MESENCHYMAL STEM CELLS TRANSPLANTATION FOR RESTORATION SCIATIC NERVE FUNCTION AFTER ITS COMPLETE RUPTURE IN RATS Piatykop V., Kaliuzhka V., Shchegelska O., Markevych M. Peripheral nerves damage is a frequent pathology with significant socio-economic significance. The aim is to study the possibility of using fibrin matrices filled with neuroinduced mesenchymal stem cells (nMSC) to restore integrity of peripheral nerves. Methods. The study was carried out on 40 mongrel female rats. Sciatic nerves (SN) of all rats were intersected and then reconstituted using various methods. nMSC were obtained from rats` bone marrow and cultivated by special method. Results. Total anatomical rupture of SN without treatment led to persistent neurologic deficit (SFI = -98) in E1 group. Partial restoration of SN function increased to SFI = -37 on the 30th day in E2 (operative reconstruction) group. Partial restoration of SN function occurred after 20 days (SFI = -64) in E3 group (transplanted acellular fibrin matrix). Partial restoration of SN function started at the 3rd day, stably increased to SFI=-27 on 30th day in E4 group (transplanted fibrin matrix with nMSC). Histological evaluation showed: there were alternating portions of connective tissue with portions of nerve fibers in E2 group; in E3 group large scar was formed at the place of transplanted fibrin matrix; in E4 were found spindle-shaped and stellate cells with long processes running from one side of SN to another, cells of connective tissue and thin nerve fibers. Conclusions. It has been shown that transplantation of the fibrin matrix with nMSC was more effective for treatment of SN trauma than transplantation of cell-free fibrin matrix and close to the results of surgical reconstruction. Keywords: mesenchymal stem cells, sciatic nerve, fibrin matrix.   Резюме ЕФЕКТИВНІТЬ ТРАНСПЛАНТАЦІЇ ФІБРИНОВИХ МАТРИЦЬ ЗНЕЙРОІНДУКОВАНИМИ МЕЗЕНХІМАЛЬНИМИ  СТОВБУРОВИМИ КЛІТИНАМИДЛЯ ВІДНОВЛЕННЯ ФУНКЦІЇ СІДНИЧНОГО НЕРВУ ПІСЛЯ ЙОГО РОЗРИВУ УЩУРІВ П’ятикоп В.О., Калюжка В.Ю., Щегельська О.А., Маркевич М.А. Пошкодження периферичних нервів є частою патологією, що має значне соціально-економічне значення. Метою роботи є вивчення можливості використання фібринових матриць, заповнених нейроиндукованими мезенхімальними стовбуровими клітинами (нМСК) для відновлення цілісності периферичних нервів. Методи. Дослідження проводили на 40 беспородних щурах. Сідничні нерви (СН) всіх щурів перетинали і потім відновлювали їх цілісність різними методами. МСК отримували з кісткового мозку щурів і культивували спеціальним методом.Результати. Загальний анатомічний розрив СН без лікування призводив до стійкого неврологічного дефіциту (Sciatic functional index (SFI) = -98) у групі Е1. Часткове відновлення функції СН зросло до SFI = -37 на 30-й день у групі E2 (оперативна реконструкція). Часткове відновлення функції СН відбувалося через 20 днів (SFI = -64) в групі Е3 (трансплантований фібриновий безклітинний матрикс). Часткове відновлення функції SN починалося на 3-й день, стабільно збільшувалося до SFI=-27 на 30-й день у групі E4 (трансплантований фібриновий матрикс з нМСК). Гістологічна оцінка показала: формувались ділянки сполучної тканини з ділянками нервових волокон у групі Е2; у групі Е3 великий сполучнотканинниий рубець утворився на місці трансплантованого фібринового матриксу; в Е4 були виявлені веретеноподібні і зірчасті клітини з довгими відросткамии від однієї сторони СН до іншої, клітини сполучної тканини і тонкі нервові волокна. Висновки. Було показано, що трансплантація фібринового матриксу з нМСК була більш ефективною для лікування травми СН, ніж трансплантація безклітинної фібринової матриці та близька до результатів хірургічної реконструкції.Ключові слові: мезенхімальні стовбурові клітини, сідничний нерв, фібринова матриця.   Резюме. ЭФЕКТИВНОСТЬ ТРАНСПЛАНТАЦИИ ФИБРИНОВЫХ МАТРИЦ С НЕЙРОИНДУЦИРОВАННЫМИ МЕЗЕНХИМАЛЬНЫМИ СТВОЛОВЫМИ КЛЕТКАМИ ДЛЯ ВОССТАНОВЛЕНИЯ ФУНКЦИИ СЕДАЛИЩНОГО НЕРВА ПОСЛЕ ЕГО РАЗРЫВА У КРЫС. Пятикоп В.А., Калюжка В.Ю., Щегельская Е.А., Маркевич Н.А. Повреждение периферических нервов является частой патологией, имеющей значительное социально-экономическое значение. Цель состоит в том, чтобы изучить возможность использования фибриновых матриц, заполненных нейроиндуцированными мезенхимальными стволовыми клетками (нМСК), для восстановления целостности периферических нервов. Методы. Исследование проведено на 40 беспородных самках крыс. Седалищные нервы (СН) всех крыс пересекали и затем восстанавливали, используя различные методы. нМСК получали из костного мозга крыс и культивировали специальным способом. Результаты. Полный анатомический разрыв СН без лечения привел к стойкому неврологическому дефициту (SFI = -98) в группе Е1. Частичное восстановление функции SN увеличилось до SFI = -37 на 30-й день в группе E2 (оперативная реконструкция). Частичное восстановление функции СН произошло через 20 дней (SFI = -64) в группе E3 (трансплантированный фибриновый бесклеточный матрикс). Частичное восстановление функции СН началось на 3-й день, стабильно увеличилось до SFI = -27 на 30-й день в группе Е4 (трансплантированный фибриновый матрикс с нМСК). Гистологическая оценка показала: в группе Е2 были чередующиеся участки соединительной ткани с нервными волокнами; в группе Е3 образовался крупный рубец на месте трансплантированного фибринового матрикса; в E4 были обнаружены веретенообразные и звездчатые клетки с длинными отростками, идущими от одной стороны СН к другой, клетками соединительной ткани и тонкими нервными волокнами. Выводы. Было показано, что трансплантация фибринового матрикса с нМСК была более эффективной для лечения травмы СН, чем трансплантация бесклеточного фибринового матрикса и близка к результатам хирургической реконструкции. Ключевые слова: мезенхимальные стволовые клетки, седалищный нерв, фибриновая матрица

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