scholarly journals Nervous Control of Movement in Annelids

1960 ◽  
Vol 37 (1) ◽  
pp. 46-56
Author(s):  
DONALD MELVIN WILSON
Keyword(s):  
Motor Neurons ◽  
Fast Response ◽  
Slow Response ◽  
Nervous Control ◽  
Chemical Stimuli ◽  
Nerve Muscle ◽  
Slow System ◽  
Fast Responses ◽  
Stimulation Of

1. Nerve muscle preparations of the segmental nerves and associated muscles have been made using a nereid polychaete, Neanthes brandti (Malmgren). 2. Two kinds of response, differing in threshold and latency, were found. The ‘fast’ response is large at the first shock and (at frequencies above 1/sec.) decreases thereafter. The ‘slow’ response is small but facilitates with repetition at frequencies above 10/sec. Facilitation reaches a maximum after 3 or 4 shocks. 3. Isolated parapodia show several distinct reflex movements to mechanical and chemical stimuli. These must involve motor neurons in the parapodial ganglion. 4. Stimulation of the segmental nerves of the leech, Hirudo, evokes facilitating muscle potentials resembling in most details those of the ‘slow‘ system in Neanthes. 5. The ‘fast’ and ‘slow’ responses are discussed in comparison with other invertebrate systems, especially those of arthropods. The ‘slow’ responses in annelids show less facilitation. The ‘fast’ responses of polychaetes fatigue quickly and are probably useful only in ‘startle’ responses.

Disopyramide phosphate effects on slow and depressed fast responses

1986 ◽  
Vol 64 (4) ◽  
pp. 487-491 ◽  
Author(s):  
Otto F. Schanne ◽  
G. Bkaily ◽  
B. Dumais ◽  
L. Boutin
Keyword(s):  
Spontaneous Activity ◽  
Action Potentials ◽  
Potassium Conductance ◽  
Fast Response ◽  
Membrane Depolarization ◽  
Neonatal Rat ◽  
Slow Response ◽  
Beating Rate ◽  
Rat Ventricle ◽  
Fast Responses

We studied the effects of disopyramide phosphate on explanted neonatal rat ventricle cells exhibiting depressed fast responses or naturally occurring slow response action potentials together with automatic activity. Disopyramide suppressed the spontaneous activity at a concentration of 2.5 μg/mL with a half-maximal value of 10 μg/mL. Before spontaneous activity was lost, there was an increase in beating rate possibly related to membrane depolarization. In depressed fast and slow response action potentials there was an increase in action potential duration (APD) which was consistently found both at the level of the plateau and at 90% repolarization. Comparison of the APD increase observed after disopyramide treatment and that after exposure to 20 mM tetraethylammonium suggested a block of a potassium conductance as a possible cause underlying the change in APD. The [Formula: see text] values of the depressed fast response decreased at constant membrane potential and this was attributed to the local anesthetic effect of the drug. In addition, we report two novel findings: (i) a decrease of [Formula: see text] of the slow response action potentials which may be secondary to membrane depolarization, and (ii) an increase in the duration of slow action potentials, possibly caused by inhibition of a potassium conductance.

Synaptic regulation of cellular properties and burst oscillations of neurons in gastric mill system of spiny lobsters, Panulirus interruptus

1984 ◽  
Vol 52 (1) ◽  
pp. 54-73 ◽  
Author(s):  
D. F. Russell ◽  
D. K. Hartline
Keyword(s):  
Motor Neurons ◽  
Pattern Generator ◽  
Stomatogastric Ganglion ◽  
Gastric Mill ◽  
Panulirus Interruptus ◽  
Synaptic Regulation ◽  
Gastric Cells ◽  
Current Pulses ◽  
Regenerative Property ◽  
Stimulation Of

The properties of neurons in the stomatogastric ganglion (STG) participating in the pattern generator for the gastric mill rhythm were studied by intracellular current injection under several conditions: during ongoing gastric rhythms, in the nonrhythmic isolated STG, after stimulation of the nerve carrying central nervous system (CNS) inputs to the STG, or under Ba2+ or Sr2+. Slow regenerative depolarizations during ongoing rhythms were demonstrated in the anterior median, cardiopyloric, lateral cardiac, gastropyloric, and continuous inhibitor (AM, CP, LC, GP, and CI) neurons according to criteria such as voltage dependency, burst triggering, and termination by brief current pulses, etc. Experiments showed that regenerative-like behavior was not due to synaptic network interactions. The slow regenerative responses were abolished by isolating the stomatogastric ganglion but could be reestablished by stimulating the input nerve. This indicates that certain CNS inputs synaptically induce the regenerative property in specific gastric neurons. Slow regenerative depolarizations were not demonstrable in gastric mill (GM) motor neurons. Their burst oscillations and firing rate were instead proportional to injected current. CNS inputs evoked a prolonged depolarization in GM motor neurons, apparently by a nonregenerative mechanism. All the gastric cells showed prolonged regenerative potentials under 0.5-1.5 mM Ba2+. We conclude that the gastric neurons of the STG can be divided into three types according to their properties: those with a regenerative capability, a repetitively firing type, and a nonregenerative "proportional" type. The cells are strongly influenced by several types of CNS inputs, including "gastric command fibers."

Connections between thoraco-coxal proprioceptive afferents and motor neurons in the locust

2000 ◽  
Vol 203 (3) ◽  
pp. 435-445
Author(s):  
M. Wildman
Keyword(s):  
Electrical Stimulation ◽  
Sensory Neurons ◽  
Motor Neurons ◽  
Chordotonal Organ ◽  
Synaptic Connections ◽  
Afferent Neurons ◽  
Postsynaptic Potentials ◽  
The Common ◽  
Proprioceptive Afferents ◽  
Stimulation Of

The position of the coxal segment of the locust hind leg relative to the thorax is monitored by a variety of proprioceptors, including three chordotonal organs and a myochordotonal organ. The sensory neurons of two of these proprioceptors, the posterior joint chordotonal organ (pjCO) and the myochordotonal organ (MCO), have axons in the purely sensory metathoracic nerve 2C (N2C). The connections made by these afferents with metathoracic motor neurons innervating thoraco-coxal and wing muscles were investigated by electrical stimulation of N2C and by matching postsynaptic potentials in motor neurons with afferent spikes in N2C. Stretch applied to the anterior rotator muscle of the coxa (M121), with which the MCO is associated, evoked sensory spikes in N2C. Some of the MCO afferent neurons make direct excitatory chemical synaptic connections with motor neurons innervating the thoraco-coxal muscles M121, M126 and M125. Parallel polysynaptic pathways via unidentified interneurons also exist between MCO afferents and these motor neurons. Connections with the common inhibitor 1 neuron and motor neurons innervating the thoraco-coxal muscles M123/4 and wing muscles M113 and M127 are polysynaptic. Afferents of the pjCO also make polysynaptic connections with motor neurons innervating thoraco-coxal and wing muscles, but no evidence for monosynaptic pathways was found.

The Function of a Heteromorph Antennule in a Spiny Lobster, Panulirus Argus

1965 ◽  
Vol 43 (1) ◽  
pp. 55-78
Author(s):  
D. M. MAYNARD ◽  
M. J. COHEN
Keyword(s):  
Motor Neurons ◽  
Spiny Lobster ◽  
Panulirus Argus ◽  
Intracellular Recordings ◽  
Afferent Fibre ◽  
The Third ◽  
Naturally Occurring ◽  
Withdrawal Response ◽  
Basic Similarity ◽  
Stimulation Of

1. The effects of electrical and mechanical stimulation upon a ‘naturally occurring’ heteromorph appendage growing in place of one eyestalk in Panulirus argus were examined. The heteromorph resembled the outer flagellum of the antennule in form. 2. Heteromorph stimulation elicited both a generalized withdrawal response, and a specific depression of the third segment and flagellum of the ipsilateral antennule. Such a depression response was also elicited upon stimulation of the ipsilateral outer flagellum of the normal antennule and by no other input investigated. 3. The basic similarity of the two responses was confirmed by electromyography and by intracellular recordings from motor neurons and interneurons within the lobster brain. 4. It was concluded that at least one afferent fibre component from the heteromorph and normal flagellum terminated upon the same interneuron pools, while avoiding others, and that consequently these observations provide evidence for the formation of functional inter-neuronal connexions according to type specificity.

Laryngeal and tracheobronchial cough in anesthetized dogs

1994 ◽  
Vol 76 (6) ◽  
pp. 2672-2679 ◽  
Author(s):  
M. Tatar ◽  
G. Sant′Ambrogio ◽  
F. B. Sant′Ambrogio
Keyword(s):  
Citric Acid ◽  
Mechanical Stimulation ◽  
Esophageal Pressure ◽  
Afferent Fibers ◽  
Anesthetized Dogs ◽  
Conduction Cooling ◽  
Chemical Stimuli ◽  
Alpha Chloralose ◽  
Tracheal Bifurcation ◽  
Stimulation Of

Tussigenic sensitivity of laryngeal and tracheobronchial regions to mechanical and chemical stimuli was compared in 22 urethan-alpha-chloralose-anesthetized dogs. In addition, the contribution of myelinated and unmyelinated vagal fibers in mediating laryngeal and tracheobronchial cough was investigated. The intensity of cough was evaluated from changes in esophageal pressure. Whereas all mechanical stimulations and citric acid inhalations into tracheobronchial region elicited cough, only 56.7% of mechanical stimulation and 33.3% of citric acid challenges to larynx were effective. The intensity of tracheobronchial cough was significantly higher than that of laryngeal cough. When mechanical stimulation was conducted under visual control (bronchofiberscope), cough elicitability was found to be higher from tracheal bifurcation and main stem bronchi (62.5–87.5%) than from any laryngeal structure (0–42.9%). During partial block of vagal conduction (cooling to 6 degrees C), mechanical and citric acid tracheobronchial stimulations failed to elicit cough and mechanical laryngeal stimulation was effective only in 1 of 10 dogs. Intensity of cough was strongly decreased when mechanical stimulation followed capsaicin administration into trachea (0.3 ml; 100 micrograms/ml) or intravenously (10 micrograms/kg). We conclude that, in anesthetized dogs, stimulation of tracheobronchial region is more effective and prompt in eliciting cough than stimulation of larynx, myelinated vagal afferent fibers play an important role in mediating mechanically and citric acid-induced tracheobronchial cough and mechanically induced laryngeal cough, and stimulation of tracheobronchial and pulmonary capsaicin-sensitive receptors strongly inhibits mechanically induced cough.

The Pedal Neurons of Aplysia Punctata

1968 ◽  
Vol 48 (1) ◽  
pp. 127-140
Author(s):  
D. A. DORSETT
Keyword(s):  
Motor Neurons ◽  
The Other ◽  
Afferent Pathways ◽  
Stimulation Of

1. Three classes of neurons have been identified in the pedal ganglia of Aplysia punctata. 2. The motor neurons, which may be unipolar or bipolar, have the axon passing into one of the pedal nerves and in the case of the bipolars, the other branch entering the pedal commissure. This synapses with neurons on the opposite side, thus providing an integrative link between the ganglia. 3. The interneurons are without axons in the pedal nerves or commissure, although afferent pathways to these cells and the motor neurons occur in the pedal nerves in a variety of combinations. 4. The pathways in the ipsilateral nerves are for the most part excitatory, but inhibitory fibres occur in the posterior pedal nerve. 5. Inhibitory potentials were often obtained in the interneurons by stimulation of the pedal commissure. 6. A second type of coordinative pathway is provided by fibres which enter the CNS in one of the pedal nerves and terminate on neurons in both pedal ganglia.

Pharmacological Properties of Excitatory Neuromuscular Synapses in the Locust

1968 ◽  
Vol 49 (2) ◽  
pp. 341-361
Author(s):  
P. N. R. USHERWOOD ◽  
P. MACHILI
Keyword(s):  
Muscle Fibres ◽  
Amino Group ◽  
Mechanical Responses ◽  
Neuromuscular Synapses ◽  
Level Of Activity ◽  
Excitatory Activity ◽  
Wide Range ◽  
Nerve Muscle ◽  
Related Compounds ◽  
Stimulation Of

1. The effects of a wide range of amino acids and related compounds on retractor unguis nerve-muscle preparations from the locust, grasshopper and cockroach have been investigated. 2. L-glutamate is the most active excitatory substance. The presence of two acidic groups and one amino group is essential for excitatory activity while the position of the amino group is of some importance in determining the level of activity. 3. When L-glutamate is applied iontophoretically to the muscle fibres, ‘glutamate’ depolarizations are recorded only at the synaptic sites. Other evidence that the action of glutamate is restricted to the synaptic sites is presented. 4. Perfusion of isolated locust retractor unguis nerve-muscle preparations with locust haemolymph does not markedly affect the neurally evoked mechanical responses. It appears that locust haemolymph contains little ‘free’ L-glutamate. 5. Four acidic amino aids have been identified in the perfusate from isolated retractor unguis preparations namely, glycine, alanine, aspartate and L-glutamate. However, only L-glutamate increases in concentration during stimulation of the retractor unguis nerve.

Whisker Movements Evoked by Stimulation of Single Motor Neurons in the Facial Nucleus of the Rat

2008 ◽  
Vol 99 (6) ◽  
pp. 2821-2832 ◽  
Author(s):  
Lucas J. Herfst ◽  
Michael Brecht
Keyword(s):  
Motor Neurons ◽  
Large Range ◽  
Facial Nucleus ◽  
Time To Peak ◽  
Coding Scheme ◽  
Movement Characteristics ◽  
Output Structure ◽  
Single Spike ◽  
Stereotyped Movement ◽  
Stimulation Of

The lateral facial nucleus is the sole output structure whose neuronal activity leads to whisker movements. To understand how single facial nucleus neurons contribute to whisker movement we combined single-cell stimulation and high-precision whisker tracking. Half of the 44 stimulated neurons gave rise to fast whisker protraction or retraction movement, whereas no stimulation-evoked movements could be detected for the remainder. Direction, speed, and amplitude of evoked movements varied across neurons. Protraction movements were more common than retraction movements ( n = 16 vs. n = 4), had larger amplitudes (1.8 vs. 0.3° for single spike events), and most protraction movements involved only a single whisker, whereas most retraction movements involved multiple whiskers. We found a large range in the amplitude of single spike-evoked whisker movements (0.06–5.6°). Onset of the movement occurred at 7.6 (SD 2.5) ms after the spike and the time to peak deflection was 18.2 (SD 4.3) ms. Each spike reliably evoked a stereotyped movement. In two of five cases peak whisker deflection resulting from consecutive spikes was larger than expected when based on linear summation of single spike-evoked movement profiles. Our data suggest the following coding scheme for whisker movements in the facial nucleus. 1) Evoked movement characteristics depend on the identity of the stimulated neuron (a labeled line code). 2) The facial nucleus neurons are heterogeneous with respect to the movement properties they encode. 3) Facial nucleus spikes are translated in a one-to-one manner into whisker movements.

Vagal control of pyloric resistance

1995 ◽  
Vol 269 (4) ◽  
pp. G558-G569 ◽  
Author(s):  
C. H. Malbert ◽  
C. Mathis ◽  
J. P. Laplace
Keyword(s):  
Gastric Emptying ◽  
Temporal Relationship ◽  
Vagal Stimulation ◽  
Simultaneous Recording ◽  
Nervous Control ◽  
Transpyloric Flow ◽  
Cervical Vagotomy ◽  
Vagal Efferents ◽  
Stimulation Of

Pyloric resistance is probably a major factor regulating gastric emptying of liquids, but its nervous control is unknown. The role of efferent vagal pathways in pyloric resistance was evaluated in 13 anesthetized pigs. Pyloric resistance was assessed by simultaneous recording of gastropyloroduodenal motility and transpyloric flow during gastric emptying of saline. Cervical vagotomy suppressed all antral pressure events, increased the number of pressure events localized at the pylorus, and decreased the frequency of the flow pulses (P < 0.05), without affecting either pyloric resistance or the characteristics of flow pulses. Electrical stimulation of the cervical and the thoracic vagi both decreased pyloric resistance by about 60% and increased the stroke volume of flow pulses (P < 0.05). The reduced pyloric resistance was mainly related to an alteration of the temporal relationship between flow pulses and pyloric pressure events. These results indicate that vagal efferents could provide inhibitory inputs to pyloric resistance. A reduction in pyloric resistance contributes to the increased flow rate observed during vagal stimulation.

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