Relationship of the Reserve Vesicle Population to Synaptic Depression in the Tergotrochanteral and Dorsal Longitudinal Muscles of Drosophila

2005 ◽  
Vol 94 (3) ◽  
pp. 2111-2119 ◽  
Author(s):  
J. H. Koenig ◽  
Kazuo Ikeda
Keyword(s):  
Active Zone ◽  
Transmitter Release ◽  
Longitudinal Muscle ◽  
Repetitive Stimulation ◽  
Repetitive Firing ◽  
Depression Curve ◽  
The Difference ◽  
Relationship Of ◽  
Longitudinal Muscles ◽  
Stimulation Of

We have previously demonstrated that Drosophila synapses possess two vesicle populations—a small active zone population replenished by “fast” recycling and a much larger reserve population replenished by a slower recycling mechanism that includes endosomal intermediates. In this paper, we demonstrate that the synapses onto the tergotrochanteral muscle (TTM) are very unusual in that they possess only the active zone vesicle population but not the reserve population. The depression characteristics to repetitive stimulation of the TTM were compared with those of the dorsal longitudinal muscle (DLM), the synapses of which possess both an active zone and a reserve population. It was observed that the TTM response depressed more quickly than that of the DLM. To further explore the possible contribution of the reserve population to release, using the shibire mutant, DLM synapses were experimentally constructed that possess only the active zone population, and their depression characteristics were compared with those of the same synapses possessing both populations. It was observed that responses from DLM synapses possessing only the active zone population depressed more quickly than the same synapses possessing both populations. These experiments were conducted under conditions of blocked recycling so that the difference in stimulation tolerance represents the contribution of the reserve population to release. Furthermore, the depression curve of the DLM synapses lacking a reserve population now closely approximated that of the TTM synapses. These data suggest that the reserve vesicle population of DLM synapses may contribute to transmitter release during repetitive firing at physiological frequencies (5–10 Hz).

Dynamics of Excitatory Transmitter Release: Analysis of Synaptic Responses in CA3 Hippocampal Neurons After Repetitive Stimulation of Afferent Fibers

1998 ◽  
Vol 79 (4) ◽  
pp. 1977-1988 ◽  
Author(s):  
Marco Canepari ◽  
Enrico Cherubini
Keyword(s):  
Transmitter Release ◽  
Hippocampal Neurons ◽  
Repetitive Stimulation ◽  
Patch Clamp Technique ◽  
Afferent Fibers ◽  
Presynaptic Mechanisms ◽  
Release Analysis ◽  
Excitatory Transmitter ◽  
Stimulation Of ◽  
Synaptic Responses

Canepari, Marco and Enrico Cherubini. Dynamics of excitatory transmitter release: analysis of synaptic responses in CA3 hippocampal neurons after repetitive stimulation of afferent fibers. J. Neurophysiol. 79: 1977–1988, 1998. The patch-clamp technique (whole cell configuration) was used to record excitatory postsynaptic currents (EPSCs) evoked by repetitive stimulation (4 pulses at 50-ms intervals) of afferent fibers in the stratum lucidum-radiatum. Different synaptic behaviors (EPSC patterns) were classified in terms of facilitation or depression of the mean amplitude of the second, third, and fourth EPSC with respect to the previous one. A large variety of EPSC patterns was observed by stimulating different afferent fibers. Experiments with the mGluR2/mGluR3 agonist 2-(2,3-dicarboxycyclopropyl)glycine (DCG-IV) (1 μM), a compound that reduces release at mossy but not at associative commissural fibers and therefore allows to identify the origin of synaptic responses, showed that particular EPSC patterns could not be associated to the activation of a specific type of synaptic input. To investigate the role of the probability of release in the dynamics of synaptic activity, the extracellular calcium concentration was varied from 0.8 to 4 mM in several experiments. EPSC patterns dominated by depression, characteristics of high release probability conditions, could be observed in the majority of the cases in the presence of higher calcium concentrations. A quantitative model for dynamics of transmitter release has been developed. Experimental results were compared with data computed with the model taking into account the probability of release and the time course of reavailability. This work indicates that short-term changes of presynaptic conditions occurring during a train of action potentials can account for the high variability of EPSC responses. The model that is proposed also suggests a general method of experimental data analysis to investigate the possible presynaptic mechanisms underlying long-lasting changes in synaptic efficacy.

Neuromuscular Physiology of the Longitudinal Muscle of the Earthworm, Lumbricus Terrestris

1974 ◽  
Vol 60 (2) ◽  
pp. 453-467
Author(s):  
C. D. DREWES ◽  
R. A. PAX
Keyword(s):  
Time Course ◽  
Longitudinal Muscle ◽  
Lumbricus Terrestris ◽  
Single Pulse ◽  
Repetitive Stimulation ◽  
Muscle Fibres ◽  
Mechanical Responses ◽  
Segmental Nerve ◽  
Earthworm Lumbricus ◽  
Stimulation Of

1. Patterns of innervation of the longitudinal muscle of the earthworm, Lumbricus terrestris, were examined electrophysiologically. 2. The longitudinal musculature of a segment is innervated by relatively few axons, a fast and slow axon being present in segmental nerve I and in the double nerve, segmental nerve II-III. 3. Single-pulse stimulation of the fast axon produces large external muscle potentials and small twitch-like contractions, which with repetitive stimulation are antifacilitating. 4. Repetitive stimulation of the slow axon produces large, slowly developing and sustained mechanical responses, with electrical and mechanical responses showing summation and facilitation. 5. The amplitude and time course of slow mechanical responses are related to the frequency of stimulation. 6. Individual longitudinal muscle fibres are innervated by either the fast or slow axon in a segmental nerve, or by both fast and slow axons. 7. No evidence was found for peripheral inhibitory innervation of the longitudinal muscle.

The rapid response of Myxicola infundibulum (Grübe)

1962 ◽  
Vol 42 (3) ◽  
pp. 527-539 ◽  
Author(s):  
M. B. V. Roberts
Keyword(s):  
Nerve Cord ◽  
Escape Response ◽  
Longitudinal Muscle ◽  
Repetitive Stimulation ◽  
Rapid Response ◽  
Direct Stimulation ◽  
Giant Fibre ◽  
Single Shock ◽  
Sufficient Strength ◽  
Stimulation Of

In Myxicola the rapid muscular response produced by direct stimulation of the nerve cord with a single shock is usually large and obeys a simple ‘all-or-nothing’ relationship to the intensity of stimulation. A single shock of sufficient strength evokes a single giant fibre impulse which produces an extensive contraction of the longitudinal muscle.The magnitude of the summated contraction obtained by repetitive stimulation of the nerve cord is found to depend on the number and frequency of the shocks, thus providing the animal with a mechanism by which, theoretically, it could grade its escape response.

scholarly journals Role of intracellular Ca2+ in stimulation-induced increases in transmitter release at the frog neuromuscular junction.

1994 ◽  
Vol 104 (2) ◽  
pp. 337-355 ◽  
Author(s):  
J E Zengel ◽  
M A Sosa ◽  
R E Poage ◽  
D R Mosier
Keyword(s):  
Neuromuscular Junction ◽  
Transmitter Release ◽  
Cyclopiazonic Acid ◽  
Progressive Increase ◽  
Repetitive Stimulation ◽  
Frog Neuromuscular Junction ◽  
Quantal Content ◽  
Carbonyl Cyanide ◽  
Stimulation Of

Under conditions of reduced quantal content, repetitive stimulation of a presynaptic nerve can result in a progressive increase in the amount of transmitter released by that nerve in response to stimulation. At the frog neuromuscular junction, this increase in release has been attributed to four different processes: first and second components of facilitation, augmentation, and potentiation (e.g., Zengel, J. E., and K. L. Magleby. 1982. Journal of General Physiology. 80:583-611). It has been suggested that an increased entry of Ca2+ or an accumulation of intraterminal Ca2+ may be responsible for one or more of these processes. To test this hypothesis, we have examined the role of intracellular Ca2+ in mediating changes in end-plate potential (EPP) amplitude during and after repetitive stimulation at the frog neuromuscular junction. We found that increasing the extracellular Ca2+ concentration or exposing the preparation to carbonyl cyanide m-chlorophenylhydrazone, ionomycin, or cyclopiazonic acid all led to a greater increase in EPP amplitude during conditioning trains of 10-200 impulses applied at a frequency of 20 impulses/s. These experimental manipulations, all of which have been shown to increase intracellular levels of Ca2+, appeared to act by increasing primarily the augmentation component of increased release. The results of this study are consistent with previous suggestions that the different components of increased release represent different mechanisms, and that Ca2+ may be acting at more than one site in the nerve terminal.

Evoked slow and unit responses of the cerebral cortex following repetitive stimulation

1960 ◽  
Vol 198 (3) ◽  
pp. 511-514
Author(s):  
L. L. Boyarsky ◽  
G. Sant'Ambrogio ◽  
D. Frazier
Keyword(s):  
Cerebral Cortex ◽  
Sensorimotor Cortex ◽  
Repetitive Stimulation ◽  
Cortical Mapping ◽  
Complete Disappearance ◽  
Slow Potentials ◽  
Relationship Of ◽  
The Relationship ◽  
Frequency Of Stimulation ◽  
Stimulation Of

Unit and slow primary responses have been compared in the sensorimotor cortex of the cat to stimulation of the radial nerve. As frequency of stimulation is increased, the amplitude of the primary decreases but remains constant at a given frequency. The evoked positive and negative phases of the primary usually disappear at frequencies below 30/sec. Unit responses, however, can still be found in a region where the primary is absent. As frequency of stimulation is raised, the unit responses begin to fail intermittently with complete disappearance of the spikes at about 60/sec. but firing can be encountered at much higher frequencies. In some preparations intermittent unit firing occurs at rates of stimulation between 500 and 1000/sec. The relationship of these findings to cortical mapping is discussed. It is concluded that these data do not support the method of mapping which depends upon the use of the evoked slow potentials.

scholarly journals Studies on the Myoneural Physiology of Echinodermata

1958 ◽  
Vol 35 (4) ◽  
pp. 712-730
Author(s):  
W. POPLE ◽  
D. W. EWER
Keyword(s):  
Electrical Stimulation ◽  
Radial Nerve ◽  
Longitudinal Muscle ◽  
Repetitive Stimulation ◽  
Apparent Absence ◽  
External Stimulation ◽  
Motor Complex ◽  
Slow Contraction ◽  
Stimulation Of ◽  
Delayed Responses

1. In the apparent absence of any immediate external stimulation the retractor muscles of Cucumaria show slow contractions which take 1-2 min to develop fully. These contractions develop the maximal possible tension and are of an all-or-nothing character. 2. The contractions are neurogenic in origin, ceasing if the retractor motor complex is destroyed and being only very rarely shown by a preparation in which the motor complex is de-afferented. 3. The slow contractions may be partially or fully inhibited by stretching the longitudinal muscle. 4. Slow contractions may be released by electrical stimulation of the radial nerve. The threshold of stimulation is higher than that for the previously described ‘quick’ and ‘delayed’ responses. 5. The slow contractions released by electrical stimulation are normally maximal, but partial slow contractions may be released in certain conditions. Slow contractions are not more frequently released by repetitive stimulation of the radial nerve. 6. The occurrence of a slow contraction modifies the characteristics of the quick and delayed responses. 7. When the activity of all five retractor muscles is recorded, co-ordinated slow responses may be observed; in such responses excitation appears to spread from one radius and to be conducted independently to the other four.

It Keeps Me Seeking

2018 ◽  
Author(s):  
Andrew Briggs ◽  
Hans Halvorson ◽  
Andrew Steane
Keyword(s):  
Evolutionary Biology ◽  
Quantum Physics ◽  
Natural World ◽  
Theological Reflection ◽  
Fine Tuning ◽  
Good Argument ◽  
The Difference ◽  
Argument From Design ◽  
Relationship Of

Two scientists and a philosopher aim to show how science both enriches and is enriched by Christian faith. The text is written around four themes: 1. God is a being to be known, not a hypothesis to be tested; 2. We set a high bar on what constitutes good argument; 3. Uncertainty is OK; 4. We are allowed to open up the window that the natural world offers us. This is not a work of apologetics. Rather, the text takes an overview of various themes and gives reactions and responses, intended to place science correctly as a valued component of the life of faith. The difference between philosophical analysis and theological reflection is expounded. Questions of human identity are addressed from philosophy, computer science, quantum physics, evolutionary biology and theological reflection. Contemporary physics reveals the subtle and open nature of physical existence, and offers lessons in how to learn and how to live with incomplete knowledge. The nature and role of miracles is considered. The ‘argument from design’ is critiqued, especially arguments from fine-tuning. Logical derivation from impersonal facts is not an appropriate route to a relationship of mutual trust. Mainstream evolutionary biology is assessed to be a valuable component of our understanding, but no exploratory process can itself fully account for the nature of what is discovered. To engage deeply in science is to seek truth and to seek a better future; it is also an activity of appreciation, as one may appreciate a work of art.

Dynamic network intelligent hybrid recommendation algorithm and its application in online shopping platform

2021 ◽  
pp. 1-13
Author(s):  
Yuxuan Gao ◽  
Haiming Liang ◽  
Bingzhen Sun
Keyword(s):  
Online Shopping ◽  
Rapid Development ◽  
Dynamic Network ◽  
Topsis Method ◽  
Recommendation Algorithm ◽  
Time Periods ◽  
The Difference ◽  
Relationship Of ◽  
Hybrid Recommendation ◽  
Novel Model

With the rapid development of e-commerce, whether network intelligent recommendation can attract customers has become a measure of customer retention on online shopping platforms. In the literature about network intelligent recommendation, there are few studies that consider the difference preference of customers in different time periods. This paper proposes the dynamic network intelligent hybrid recommendation algorithm distinguishing time periods (DIHR), it is a integrated novel model combined with the DEMATEL and TOPSIS method to solved the problem of network intelligent recommendation considering time periods. The proposed method makes use of the DEMATEL method for evaluating the preference relationship of customers for indexes of merchandises, and adopt the TOPSIS method combined with intuitionistic fuzzy number (IFN) for assessing and ranking the merchandises according to the indexes. We specifically introduce the calculation steps of the proposed method, and then calculate its application in the online shopping platform.

scholarly journals Interactional mechanisms of Paenibacillus polymyxa SC2 and pepper (Capsicum annuum L.) suggested by transcriptomics

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hu Liu ◽  
Yufei Li ◽  
Ke Ge ◽  
Binghai Du ◽  
Kai Liu ◽  
...  
Keyword(s):  
Capsicum Annuum ◽  
Biofilm Formation ◽  
Rhizosphere Soil ◽  
Paenibacillus Polymyxa ◽  
Systemic Resistance ◽  
Expression Of Genes ◽  
Transcription Factor Genes ◽  
Transcription Regulators ◽  
Relationship Of ◽  
Stimulation Of

Abstract Background Paenibacillus polymyxa SC2, a bacterium isolated from the rhizosphere soil of pepper (Capsicum annuum L.), promotes growth and biocontrol of pepper. However, the mechanisms of interaction between P. polymyxa SC2 and pepper have not yet been elucidated. This study aimed to investigate the interactional relationship of P. polymyxa SC2 and pepper using transcriptomics. Results P. polymyxa SC2 promotes growth of pepper stems and leaves in pot experiments in the greenhouse. Under interaction conditions, peppers stimulate the expression of genes related to quorum sensing, chemotaxis, and biofilm formation in P. polymyxa SC2. Peppers induced the expression of polymyxin and fusaricidin biosynthesis genes in P. polymyxa SC2, and these genes were up-regulated 2.93- to 6.13-fold and 2.77- to 7.88-fold, respectively. Under the stimulation of medium which has been used to culture pepper, the bacteriostatic diameter of P. polymyxa SC2 against Xanthomonas citri increased significantly. Concurrently, under the stimulation of P. polymyxa SC2, expression of transcription factor genes WRKY2 and WRKY40 in pepper was up-regulated 1.17-fold and 3.5-fold, respectively. Conclusions Through the interaction with pepper, the ability of P. polymyxa SC2 to inhibit pathogens was enhanced. P. polymyxa SC2 also induces systemic resistance in pepper by stimulating expression of corresponding transcription regulators. Furthermore, pepper has effects on chemotaxis and biofilm formation of P. polymyxa SC2. This study provides a basis for studying interactional mechanisms of P. polymyxa SC2 and pepper.

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