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.

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.

Putative mechanisms involved in excitatory and inhibitory effects of somatostatin on intestinal motility

1989 ◽  
Vol 257 (4) ◽  
pp. G532-G538 ◽  
Author(s):  
T. Takeda ◽  
K. Taniyama ◽  
S. Baba ◽  
C. Tanaka
Keyword(s):  
Electrical Stimulation ◽  
Longitudinal Muscle ◽  
Cholinergic Neuron ◽  
Gamma Aminobutyric Acid ◽  
Inhibitory Effects ◽  
Guinea Pig Ileum ◽  
Excitatory Effect ◽  
Ergic Neuron ◽  
Gabaa Antagonist ◽  
Stimulation Of

The mechanism of action of somatostatin on the motility of intestine was examined in the entire preparation and the longitudinal muscle attached with Auerbach's plexus (LA) preparation of guinea pig ileum, in relation to the cholinergic neuron and gamma-aminobutyric acid (GABA)ergic neuron. Somatostatin produced a transient potentiation of electrical stimulation-induced twitch contractions followed by an inhibition. The excitatory effect of somatostatin was associated with an increase in the release of [3H]acetylcholine (ACh) from the preparations preloaded with [3H]choline. Bicuculline, a GABAA antagonist, inhibited the somatostatin-induced excitatory effect. Somatostatin inhibited the electrical stimulation-induced twitch contraction and release of [3H]ACh, and the inhibition was greater in the entire preparation than in the LA. Phaclofen, a GABAB antagonist, prevented the inhibitory effects of somatostatin. Somatostatin induced a Ca2+ -dependent, tetrodotoxin-sensitive release of [3H]GABA from the preparations preloaded with [3H]GABA. Therefore somatostatin exerts excitatory and inhibitory effects on the cholinergic neuron due to the stimulation of the GABAergic neuron, and the motility of the intestine is regulated.

Polarity of effects of stimulation of Auerbach's plexus on longitudinal muscle.

1978 ◽  
Vol 235 (4) ◽  
pp. E345
Author(s):  
S Yokoyama ◽  
T Ozaki
Keyword(s):  
Electrical Stimulation ◽  
Longitudinal Muscle ◽  
Oral Side ◽  
Metal Microelectrode ◽  
Rabbit Intestine ◽  
Auerbach’S Plexus ◽  
Repetitive Electrical Stimulation ◽  
Auerbach's Plexus ◽  
Anal Side ◽  
Stimulation Of

The effects of repetitive electrical stimulation of nodes in Auerbach's plexus on the longitudinal muscle of rabbit intestine were investigated. Peeled longitudinal muscle strips, with adherent Auerbach's plexus, were obtained and placed under a stereodissecting microscope. Neural elements within nodes of Auerbach's plexus were stimulated repetitively using a metal microelectrode with tip diameter of 5 micrometer. Stimuli applied to a node generally caused excitation of the longitudinal muscle on the oral side and inhibition on the anal side of the point of stimulation. Excitation of the muscle was mainly cholinergic, and inhibition of the muscle was nonadrenergic. From the results of the present study the concept of the law of the intestine, excitation above and inhibition below the stimulated spot, was supported.

Several days of muscle hyperalgesia facilitates cortical somatosensory excitability

2017 ◽  
Vol 16 (1) ◽  
pp. 169-169
Author(s):  
E. De Martino ◽  
L. Petrini ◽  
S. Schabrun ◽  
T. Graven-Nielsen
Keyword(s):  
Chronic Pain ◽  
Electrical Stimulation ◽  
Eccentric Exercise ◽  
Radial Nerve ◽  
Muscle Soreness ◽  
Neural Circuits ◽  
Pain Thresholds ◽  
Pressure Pain Thresholds ◽  
Sensory Evoked ◽  
Stimulation Of

Abstract Background and aims Maladaptive plasticity in neural circuits has been proposed in chronic musculoskeletal pain and has been discussed as a key component of the transition from acute to chronic pain. The induction of delayed onset muscle soreness (DOMS) in healthy individuals is one method that can be used to investigate the adaptations of neural circuits in response to several days of muscle hyperalgesia. The aim of this study was to determine the adaptations of the sensory cortex in response to muscle hyperalgesia induced by eccentric exercise of the wrist extensor muscles. It was hypothesized that muscle hyperalgesia would result in a facilitation of cortical somatosensory excitability, based on sensory evoked potentials evoked by electrical stimulation of the radial nerve. Methods Twelve healthy subjects performed eccentric exercise of the wrist extensors. Muscle soreness, pressure pain thresholds (PPTs) on the extensor carpi radialis (ECR) muscle, somatosensory evoked potentials (SEPs) based on 10 channel EEG recorded during electrical stimulation of the radial nerve were recorded before (Day0Pre), 2h (Day0Post), 2 days (Day2), and 6 days (Day6) after exercise. Results Compared to Day0Pre: (i) Muscle soreness increased at Day0Post and increased further at Day2 (both P < 0.05). (ii) Pressure pain thresholds decreased at Day2 (P < 0.05), (iii) the peak-to-peak N30-P45 and P45-N60 amplitude of the sensory evoked potential from the central-parietal recording sites were increased at Day2 (both P < 0.05); (iv) reduction in ECR PPTs was correlated with an increase of the post-central P45 wave. ConclusionsThese data demonstrate that hyperalgesia developing across several days is accompanied by an increase in sensory cortical excitability. In addition, sensory cortical adaptation followed a similar temporal profile to increased sensitivity to pressure (PPTs). This model may be relevant for further understanding neural adaptation in the transition from acute to chronic pain.

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.

Alteration of Contractile Response of Artery Strips by a Potassium-Free Solution, Cardiac Glycosides and Changes in Stimulation Frequency

1957 ◽  
Vol 189 (1) ◽  
pp. 185-190 ◽  
Author(s):  
Edward Leonard
Keyword(s):  
Smooth Muscle ◽  
Electrical Stimulation ◽  
Cardiac Glycosides ◽  
Contractile Response ◽  
Initial Period ◽  
Repetitive Stimulation ◽  
Free Medium ◽  
Relaxation Cycle ◽  
Time Required ◽  
Stimulation Of

Electrical stimulation of helically cut strips of rabbit carotid artery, mounted so as to allow development of tension isometrically, causes a contraction-relaxation cycle which remains reproducible for many hours, after an initial period of rising contractile response. If the strip is equilibrated in a potassium-free Krebs solution, or if a cardiac glycoside is added, the tension developed on electrical stimulation increases, the time required for relaxation is prolonged and contracture may also be observed. Desoxycorticosterone or progesterone decrease the contractile response of the strip. The arterial smooth muscle strip also exhibits the staircase phenomenon, a stepwise increase in tension on repeated stimulation after a period of rest. It is suggested that the changes in contractile response induced by a potassium-free medium, addition of glycosides, or repetitive stimulation are related to a loss of muscle fiber potassium. The action of the glycosides on the artery strip is discussed from the viewpoint of a model mechanism for altering vascular smooth muscle activity by affecting intracellular electrolytes.

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).

Further Studies on Synaptic Transmission in Insects

1971 ◽  
Vol 55 (1) ◽  
pp. 123-149
Author(s):  
J. J. CALLEC ◽  
J. C. GUILLET ◽  
Y. PICHON ◽  
J. BOISTEL
Keyword(s):  
Electrical Stimulation ◽  
Firing Pattern ◽  
Giant Axon ◽  
Repetitive Stimulation ◽  
Limiting Factors ◽  
Single Receptor ◽  
Presynaptic Spike ◽  
Chemical Synapses ◽  
Giant Interneurone ◽  
Stimulation Of

1. Some integrative properties of the chemical synapses between the sensory cereal afferent fibres and a giant axon are studied at the unitary level by external recording. 2. Unitary monosynaptic EPSPs are related to cereal receptor activity, one presynaptic spike inducing one EPSP. Unitary IPSPs are not directly related to cereal activity. They seem to originate within a ganglion. 3. Many receptors make synaptic contacts with a given giant axon. When a single receptor is strongly stimulated, the summation of elementary induced EPSPs gives a postsynaptic depolarization which is not able to reach the threshold. The simultaneous stimulation of several receptors provides a considerable amount of postsynaptic depolarization, thus triggering one or two spikes, rarely more. 4. The postsynaptic responses appear to be more or less different according to the afferent firing pattern: phasic, phasic-tonic and tonic. Some factors modulate these schemes: (a) Potentiation, which occurs only with phasic patterns, thus increasing their postsynaptic effect, is followed by a longer component of depression. (b) Limiting factors, such as fatigue phenomenon, are thought to be essentially related to depletion of an available transmitter. 5. Synchronous electrical stimulation induces a monosynaptic response, later followed by a complex polysynaptic phenomenon. These responses decrease with repetitive stimulation, but the former is far less labile than the latter. 6. These studies seem to indicate that a giant interneurone in the cockroach fires only in special conditions, namely when a strong mechanical stimulation occurs after a noticeable period of rest. This spike is then rapidly conducted to higher centres without relay.

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