The whole-body withdrawal response of Lymnaea stagnalis. I. Identification of central motoneurones and muscles

1991 ◽  
Vol 158 (1) ◽  
pp. 63-95 ◽  
Author(s):  
G. P. Ferguson ◽  
P. R. Benjamin
Keyword(s):  
Action Potentials ◽  
Lymnaea Stagnalis ◽  
Contralateral Side ◽  
The Body ◽  
Whole Body ◽  
Muscle Fibres ◽  
Strongly Coupled ◽  
Weakly Coupled ◽  
Synchronous Contraction ◽  
Withdrawal Response

Two muscle systems mediated the whole-body withdrawal response of Lymnaea stagnalis: the columellar muscle (CM) and the dorsal longitudinal muscle (DLM). The CM was innervated by the columellar nerves and contracted longitudinally to shorten the ventral head-foot complex and to pull the shell forward and down over the body. The DLM was innervated by the superior and inferior cervical nerves and the left and right parietal nerves. During whole-body withdrawal, the DLM contracted synchronously with the CM and shortened the dorsal head-foot longitudinally. The CM and the DLM were innervated by a network of motoneurones. The somata of these cells were located in seven ganglia of the central nervous system (CNS), but were especially concentrated in the bilaterally symmetrical A clusters of the cerebral ganglia. The CM was innervated by cells in the cerebral and pedal ganglia and the DLM by cells in the cerebral, pedal, pleural and left parietal ganglia. Individual motoneurones innervated large, but discrete, areas of muscle, which often overlapped with those innervated by other motoneurones. Motoneuronal action potentials evoked one-for-one non-facilitating excitatory junction potentials within muscle fibres. No all-or-nothing action potentials were recorded in the CM or DLM, and they did not appear to be innervated by inhibitory motoneurones. The whole network of motoneurones was electrotonically coupled, with most cells on one side of the CNS strongly coupled to each other but weakly coupled to cells on the contralateral side of the CNS. This electrotonic coupling between motoneurones is probably important in producing synchronous contraction of the CM and DLM when the animal retracts its head-foot complex during whole-body withdrawal.

The whole-body withdrawal response of Lymnaea stagnalis. II. Activation of central motoneurones and muscles by sensory input

1991 ◽  
Vol 158 (1) ◽  
pp. 97-116 ◽  
Author(s):  
G. P. Ferguson ◽  
P. R. Benjamin
Keyword(s):  
Action Potentials ◽  
Sensory Input ◽  
Lymnaea Stagnalis ◽  
Intact Animal ◽  
The Body ◽  
Resting Potential ◽  
Whole Body ◽  
Withdrawal Response ◽  
Stimulation Of

The role of centrally located motoneurones in producing the whole-body withdrawal response of Lymnaea stagnalis (L.) was investigated. The motoneurones innervating the muscles used during whole-body withdrawal, the columellar muscle (CM) and the dorsal longitudinal muscle (DLM) were cells with a high resting potential (−60 to −70 mV) and thus a high threshold for spike initiation. In both semi-intact and isolated brain preparations these motoneurones showed very little spontaneous spike activity. When spontaneous firing was seen it could be correlated with the occurrence of two types of spontaneous excitatory postsynaptic potential (EPSP). One was a unitary EPSP that occasionally caused the initiation of single action potentials. The second was a larger-amplitude, long-duration (presumably compound) EPSP that caused the motoneurones to fire a burst of high-frequency action potentials. This second type of EPSP activity was associated with spontaneous longitudinal contractions of the body in semi-intact preparations. Tactile stimulation of the skin of Lymnaea evoked EPSPs in the CM and DLM motoneurones and in some other identified cells. These EPSPs summated and usually caused the motoneurone to fire action potentials, thus activating the withdrawal response muscles and causing longitudinal contraction of the semi-intact animal. Stimulating different areas of the body wall demonstrated that there was considerable sensory convergence on the side of the body ipsilateral to stimulation, but less on the contralateral side. Photic (light off) stimulation of the skin of Lymnaea also initiated EPSPs in CM and DLM motoneurones and in some other identified cells in the central nervous system (CNS). Cutting central nerves demonstrated that the reception of this sensory input was mediated by dermal photoreceptors distributed throughout the epidermis. The activation of the CM and DLM motoneurones by sensory input of the modalities that normally cause the whole-body withdrawal of the intact animal demonstrates that these motoneurones have the appropriate electrophysiological properties for the role of mediating whole-body withdrawal.

Coordination of locomotor and cardiorespiratory networks of Lymnaea stagnalis by a pair of identified interneurones

1991 ◽  
Vol 158 (1) ◽  
pp. 37-62 ◽  
Author(s):  
N. I. Syed ◽  
W. Winlow
Keyword(s):  
Body Wall ◽  
Lymnaea Stagnalis ◽  
The Body ◽  
Whole Body ◽  
Pond Snail ◽  
Selective Ablation ◽  
The Central Nervous System ◽  
Body Wall Muscles ◽  
Bilateral Pair ◽  
Left And Right

1. The morphology and electrophysiology of a newly identified bilateral pair of interneurones in the central nervous system of the pulmonate pond snail Lymnaea stagnalis is described. 2. These interneurones, identified as left and right pedal dorsal 11 (L/RPeD11), are electrically coupled to each other as well as to a large number of foot and body wall motoneurones, forming a fast-acting neural network which coordinates the activities of foot and body wall muscles. 3. The left and right sides of the body wall of Lymnaea are innervated by left and right cerebral A cluster neurones. Although these motoneurones have only ipsilateral projections, they are indirectly electrically coupled to their contralateral homologues via their connections with L/RPeD11. Similarly, the activities of left and right pedal G cluster neurones, which are known to be involved in locomotion, are also coordinated by L/RPeD11. 4. Selective ablation of both neurones PeD11 results in the loss of coordination between the bilateral cerebral A clusters. 5. Interneurones L/RPeD11 are multifunctional. In addition to coordinating motoneuronal activity, they make chemical excitatory connections with heart motoneurones. They also synapse upon respiratory motoneurones, hyperpolarizing those involved in pneumostome opening (expiration) and depolarizing those involved in pneumostome closure (inspiration). 6. An identified respiratory interneurone involved in pneumostome closure (visceral dorsal 4) inhibits L/RPeD11 together with all their electrically coupled follower cells. 7. Both L/RPeD11 have strong excitatory effects on another pair of electrically coupled neurones, visceral dorsal 1 and right parietal dorsal 2, which have previously been shown to be sensitive to changes in the partial pressure of environmental oxygen (PO2). 8. Although L/RPeD11 participate in whole-body withdrawal responses, electrical stimulation applied directly to these neurones was not sufficient to induce this behaviour.

Isolated Giant Smooth Muscle Fibres in Beroe Ovata: Ionic Dependence of Action Potentials Reveals Two Distinct Types of Fibre

1988 ◽  
Vol 135 (1) ◽  
pp. 343-362 ◽  
Author(s):  
ANDRÉ BILBAUT ◽  
ROBERT W. MEECH ◽  
MARI-LUZ HERNANDEZ-NICAISE
Keyword(s):  
Smooth Muscle ◽  
Action Potential ◽  
Action Potentials ◽  
Marine Invertebrate ◽  
The Body ◽  
Fibre Types ◽  
Resting Membrane Potential ◽  
Muscle Fibres ◽  
Beroe Ovata ◽  
Radial Muscle

1. The ionic dependence of action potentials evoked in giant smooth muscle fibres isolated by enzymatic digestion from the body wall of the marine invertebrate Beroe ovata (Ctenophora) has been investigated using conventional electrophysiological techniques. 2. Differences were observed in the two fibre types studied. The resting membrane potential was −60 ± 1.35 mV (N = 25) in longitudinal muscle fibres and −66 ±1.37 mV (N=32) in radial fibres. Action potentials had a short plateau in longitudinal fibres but not in radial fibres. 3. The action potential overshoot of both fibre types was decreased in Ca2+-free artificial sea water (ASW). In Na+-deficient ASW, action potentials could not be generated in radial fibres and showed a reduced overshoot in longitudinal fibres. 4. Tetrodotoxin (10−5moll−5) added to ASW or Ca2+-free ASW did not affect the action potentials of either type of fibre. 5. Action potentials of both fibres were partially blocked by Co2+ (20–50 mmoll−1) or Cd2+ (l-2mmoll−1). Action potentials of longitudinal fibres in Na+-deficient ASW were abolished by Co2+ (20mmoll−1). In Ca2+-free ASW, the ction potential overshoots of both sets of fibres were restored following the addition of Sr2+ or Ba2+. In longitudinal fibres, Sr2+ increased the duration of the action potential plateau. In both longitudinal and radial muscle fibres, Ba2+ prolonged the action potential. 6. In longitudinal fibres exposed to tetraethylammonium chloride (TEAC1) or 4-aminopyridine (4AP), the action potential was slightly prolonged. In these fibres, TEA+ or 4AP added to Ca2+-free ASW induced only a long-lasting depolarizing plateau. In radial fibres, the action potential duration was slightly increased in the presence of TEA+; it was unaffected by 4AP. In Ca2+-free ASW, TEA+ and 4AP induced an oscillating membrane response which appeared to be dependent on the intensity of the injected current pulse. 7. It is concluded that (a) there are significant differences between the action potentials of longitudinal and radial muscle fibres but that both are dependent on Na+ and Ca2+, (b) in longitudinal fibres, a Ca2+-activated K+ conductance and a TEA+-sensitive voltage-activated K+ conductance contribute to the repolarizing phase of the action potential, the former being predominant, (c) in radial fibres, the repolarizing phase of action potentials probably involves different membrane K+ conductances among which is a TEA+-sensitive K+ conductance.

The Organization of the Muscular System of Metridium senile

1951 ◽  
Vol s3-92 (17) ◽  
pp. 27-54
Author(s):  
E. J. BATHAM ◽  
C. F.A. PANTIN
Keyword(s):  
Body Wall ◽  
Functional Organization ◽  
Circular Muscle ◽  
Muscle Layer ◽  
The Body ◽  
Whole Body ◽  
Retractor Muscle ◽  
Muscle Fibres ◽  
Muscular System ◽  
Longitudinal Contraction

I. The muscular system of Metridium consists of fields of relatively short muscle-fibres. In extension these may exceed I mm. in length but are only about 0.5µ thick. They can shorten to about a fifth of the extended length. The fibres consist almost entirely of densely staining material. They form a connected network. At least in some cases the cells seem to be in contact rather than to form syncytial connexions. 2. Deformation of the body-wall is in part controlled by the contractility of the muscle-fibres and in part by the properties of the mesogloea. Longitudinal contraction of the body-wall is accompanied by great thickening of the substance of the mesogloea. That part of the mesogloea which carries the circular muscle-fibres of the body-wall does not thicken. It buckles, thereby throwing the muscular layer into folds. Buckling occurs during the shortening of almost every actinian tissue. The familiar folding seen in cross-sections of the retractors is a special case of excessive buckling which is permanent. 3. A natural limit to the extension of anemone tissue is reached when the muscle-layer is completely unbuckled. If contraction proceeds to a maximum, there is a second order of buckling by which the whole body-wall is thrown into folds. Con-traction ca n then proceed no further. 4. The function of the muscle-fields is analysed. The youngest cycles of mesenteries (‘imperfect microcnemes’) supply the longitudinal musculature of the column (parietal muscle). The older ‘imperfect retractor-bearers’ have only feeble parietal musculature, but possess a retractor muscle connecting the oral with the pedal disk. The perfect mesenteries have a similar organization to the imperfect retractor-bearers, and parti-cularly in the non-directive perfect mesenteries there is a well-developed sheet of radial (exocoelic) muscle whose reflex contraction opens the mouth. The vertical endocoelic muscle-fibres of all non-directive mesenteries fan out on to the pedal disk. On the exocoelic side, the parieto-basilarfans out from the pedal disk to the body-wall. As usual, the muscle-fields of the directives are developed on opposite sides from those of the non-directives. 5. The muscular plan of the pedal disk is compared with the tube foot of Asterias as described by J. E. Smith. There is a significant functional similarit y in the opera-tion of vertical, oblique, and radial muscles (basilars) bearing on the adhesive disk. The circular layer of the actinian foot has no analogue in the tube foot. It is primarily concerned with locomotion and not with adhesion. 6. The functional organization of the oral disk and tentacles is discussed. It differs from the rest of the body in the retention of ectodermal longitudinal muscle. This layer is responsible for the special movements executed in feeding. The significance of its physiological separation from the endodermal system is noted.

Electrophysiology of the peripheral nerve net in the polyclad flatworm Freemania litoricola

1975 ◽  
Vol 62 (2) ◽  
pp. 469-479
Author(s):  
H. Koopowitz
Keyword(s):  
Action Potentials ◽  
Body Wall ◽  
Contralateral Side ◽  
The Body ◽  
Conducting System ◽  
Response Decrement ◽  
Posterior Portion ◽  
Nerve Net ◽  
Tactile Stimuli ◽  
The Brain

1. A diffuse-conducting system close to the dorsal epithelium of the polyclad flatworm Freemania litoricola is described. Tactile stimuli elicit small action potentials which can be conducted around lesions through the body wall. The potentials can occur in bursts or barrages. 2. This conducting system appears to be insensitive to Mg2+ ions. 3. Conduction velocities (0–26--71 m/sec) vary over the animal. Conduction spread in the anterior half of the animal appears to be greater than that in the posterior portion. 4. Response decrement to repeated stimulation can be recorded in the peripheral system but it is not clear if this is due to habituation or fatigue. 5. Conduction from the peripheral net to the brain occurs. Some central units appear to pick up information only, or mainly, through the anterior nerves, while other units can respond to information conducted through the network to nerves of the contralateral side. 6. Different possibilities to account for this system are discussed, and it is suggested that the animals either possess a unique Mg2+ insensitive synaptic nerve-net or else the network is electrically coupled.

A Simple and Inexpensive Clinical Whole Body Counter

1976 ◽  
Vol 15 (05) ◽  
pp. 248-253
Author(s):  
A. K. Basu ◽  
S. K. Guha ◽  
B. N. Tandon ◽  
M. M. Gupta ◽  
M. ML. Rehani
Keyword(s):  
The Body ◽  
Whole Body ◽  
Vitro Assay ◽  
Body Counter ◽  
Optimum Parameters ◽  
Whole Body Counter ◽  
Single Detector ◽  
Background Index ◽  
Iodide Crystal

SummaryThe conventional radioisotope scanner has been used as a whole body counter. The background index of the system is 10.9 counts per minute per ml of sodium iodide crystal. The sensitivity and derived sensitivity parameters have been evaluated and found to be suitable for clinical studies. The optimum parameters for a single detector at two positions above the lying subject have been obtained. It has been found that for the case of 131I measurement it is possible to assay a source located at any point in the body with coefficient of variation less than 5%. To add to the versatility, a fixed geometry for in-vitro counting of large samples has been obtained. The retention values obtained by the whole body counter have been found to correlate with those obtained by in-vitro assay of urine and stool after intravenous administration of 51Cr-albumin.

Visualization of Invasion into the Body and Internal Diffusion of Nanoparticles

2008 ◽  
Vol 396-398 ◽  
pp. 569-572
Author(s):  
Fumio Watari ◽  
Shigeaki Abe ◽  
I.D. Rosca ◽  
Atsuro Yokoyama ◽  
Motohiro Uo ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Fluorescent Microscopy ◽  
The Body ◽  
Internal Diffusion ◽  
Whole Body ◽  
X Ray ◽  
Body Level ◽  
Organ Level ◽  
Level 2 ◽  
Internal Body

Nanoparticles may invade directly into the internal body through the respiratory or digestive system and diffuse inside body. The behavior of nanoparticles in the internal body is also essential to comprehend for the realization of DDS. Thus it is necessary to reveal the internal dynamics for the proper treatments and biomedical applications of nanoparticles. In the present study the plural methods with different principles such as X-ray scanning analytical microscope (XSAM), MRI and Fluorescent microscopy were applied to enable the observation of the internal diffusion of micro/nanoparticles in the (1) whole body level, (2) inner organ level and (3) tissue and intracellular level. Chemical analysis was also done by ICP-AES for organs and compared with the results of XSAM mapping.

scholarly journals Potentiometric measurement of membrane action potentials in frog muscle fibres

1966 ◽  
Vol 183 (1) ◽  
pp. 152-166 ◽  
Author(s):  
B. Frankenhaeuser ◽  
B. D. Lindley ◽  
R. S. Smith
Keyword(s):  
Action Potentials ◽  
Frog Muscle ◽  
Muscle Fibres ◽  
Membrane Action ◽  
Potentiometric Measurement

scholarly journals Making the choice between bioelectrical impedance measures for body hydration status assessment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dmitry M. Davydov ◽  
Andrey Boev ◽  
Stas Gorbunov
Keyword(s):  
Body Schema ◽  
Bioelectrical Impedance ◽  
Information Criterion ◽  
The Body ◽  
Whole Body ◽  
Hydration Status ◽  
Status Assessment ◽  
Best Fitting ◽  
Body Compartments ◽  
Fitting In

AbstractSituational or persistent body fluid deficit (i.e., de- or hypo-hydration) is considered a significant health risk factor. Bioimpedance analysis (BIA) has been suggested as an alternative to less reliable subjective and biochemical indicators of hydration status. The present study aimed to compare various BIA models in the prediction of direct measures of body compartments associated with hydration/osmolality. Fish (n = 20) was selected as a biological model for physicochemically measuring proximate body compartments associated with hydration such as water, dissolved proteins, and non-osseous minerals as the references or criterion points. Whole-body and segmental/local impedance measures were used to investigate a pool of BIA models, which were compared by Akaike Information Criterion in their ability to accurately predict the body components. Statistical models showed that ‘volumetric-based’ BIA measures obtained in parallel, such as distance2/Rp, could be the best approach in predicting percent of body moisture, proteins, and minerals in the whole-body schema. However, serially-obtained BIA measures, such as the ratio of the reactance to resistance and the resistance adjusted for distance between electrodes, were the best fitting in predicting the compartments in the segmental schema. Validity of these results should be confirmed on humans before implementation in practice.

scholarly journals Integumentary Colour Allocation in the Stork Family (Ciconiidae) Reveals Short-Range Visual Cues for Species Recognition

Birds ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 138-146
Author(s):  
Eduardo J. Rodríguez-Rodríguez ◽  
Juan J. Negro
Keyword(s):  
Short Range ◽  
Visual Cues ◽  
Species Recognition ◽  
The Body ◽  
Whole Body ◽  
Divergent Evolution ◽  
Black And White ◽  
Extant Species ◽  
Chromatic Spectrum ◽  
Mixed Species Flocks

The family Ciconiidae comprises 19 extant species which are highly social when nesting and foraging. All species share similar morphotypes, with long necks, a bill, and legs, and are mostly coloured in the achromatic spectrum (white, black, black, and white, or shades of grey). Storks may have, however, brightly coloured integumentary areas in, for instance, the bill, legs, or the eyes. These chromatic patches are small in surface compared with the whole body. We have analyzed the conservatism degree of colouration in 10 body areas along an all-species stork phylogeny derived from BirdTRee using Geiger models. We obtained low conservatism in frontal areas (head and neck), contrasting with a high conservatism in the rest of the body. The frontal areas tend to concentrate the chromatic spectrum whereas the rear areas, much larger in surface, are basically achromatic. These results lead us to suggest that the divergent evolution of the colouration of frontal areas is related to species recognition through visual cue assessment in the short-range, when storks form mixed-species flocks in foraging or resting areas.

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