Classification of Nerve Cells Dissociated From Tentacles of the Sea Anemone Calliactis parasitica

1996 ◽  
Vol 190 (1) ◽  
pp. 111-124 ◽  
Author(s):  
L. D. Saripalli ◽  
J. A. Westfall
Keyword(s):  
Nerve Cells ◽  
Sea Anemone ◽  
Calliactis Parasitica

A Transmesogloeal Conduction System in the Swimming Sea Anemone Stomphia

1980 ◽  
Vol 87 (1) ◽  
pp. 45-52
Author(s):  
I.D. LAWN
Keyword(s):  
Electrical Activity ◽  
Conduction System ◽  
Nerve Cells ◽  
Sea Anemone

1. A conduction system in Stomphia transfers information across the mesogloea from ectodermal receptors to endodermal effectors. 2. In the column, this transmesogloeal system has numerous and widespread connexions. 3. It is suggested that the connexions may be processes from multipolar nerve cells located in the endoderm. 4. Certain aspects of behaviour are controlled by this conduction system which provides yet another pathway to co-ordinate electrical activity.

The Behaviour and Neuromuscular System of Gonactinia Prolifera, A Swimming Sea-Anemone

1971 ◽  
Vol 55 (3) ◽  
pp. 611-640
Author(s):  
ELAINE A. ROBSON
Keyword(s):  
Electrical Stimulation ◽  
Mechanical Stimulation ◽  
Motor Units ◽  
Nerve Cells ◽  
Sea Anemone ◽  
Neuromuscular System ◽  
Sea Anemones ◽  
Nerve Net ◽  
Local Contraction ◽  
Electric Shocks

1. In Gonactinia well-developed ectodermal muscle and nerve-net extend over the column and crown and play an important part in the anemone's behaviour. 2. Common sequences of behaviour are described. Feeding is a series of reflex contractions of different muscles by means of which plankton is caught and swallowed. Walking, in the form of brief looping steps, differs markedly in that it continues after interruptions. Anemones also swim with rapid tentacle strokes after contact with certain nudibranch molluscs, strong mechanical disturbance or electrical stimulation. 3. Swimming is attributed to temporary excitation of a diffuse ectodermal pacemaker possibly situated in the upper column. 4. From the results of electrical and mechanical stimulation it is concluded that the endodermal neuromuscular system resembles that of other anemones but that the properties of the ectodermal neuromuscular system require a new explanation. The size and spread of responses to electric shocks vary with intensity, latency is variable and there is a tendency to after-discharge. There is precise radial localization, for example touching a tentacle or the column causes it to bend towards or away from the stimulus. 5. A model to explain these and other features includes multipolar nerve cells closely linked to the nerve-net which would act as intermediate motor units, causing local contraction of the ectodermal muscle. This scheme can be applied to other swimming anemones but there is no evidence that it holds for sea anemones generally.

The Nature of Tissue Regeneration After Wounding in the Sea Anemone Calliactis Parasitica (Couch)

1974 ◽  
Vol 54 (3) ◽  
pp. 599-617 ◽  
Author(s):  
Jane A. C. Young
Keyword(s):  
Tissue Regeneration ◽  
Sea Anemone ◽  
Calliactis Parasitica

Regeneration of ectoderm and mesogloea, and the interactions of these layers, in the sea anemone Calliactis parasitica (Couch) have been studied by examining the healing of simple wounds. Studies included the part played by the mesogloeal cells, the origin and functions of which have been much debated.

Control of mouth opening and pharynx protrusion during feeding in the sea anemone Calliactis parasitica

1975 ◽  
Vol 63 (3) ◽  
pp. 615-626
Author(s):  
I. D. McFarlane
Keyword(s):  
Amino Acids ◽  
Electrical Stimulation ◽  
Reduced Glutathione ◽  
Mouth Opening ◽  
Pulse Frequency ◽  
Sea Anemone ◽  
Conducting System ◽  
Nerve Net ◽  
Calliactis Parasitica ◽  
Stimulation Of

1. Activity in all three known conducting systems (the nerve net, SS1, and SS2) may accompany feeding in Calliactis. The most marked response is an increase in pulse frequency in the SS2 (the endodermal slow conducting system) during mouth opening and pharynx protrusion. 2. Electrical stimulation of the SS2 at a frequency of one shock every 5 s elicits mouth opening and pharynx protrusion in the absence of food. 3. A rise in SS2 pulse frequency is also evoked by food extracts, some amino acids, and in particular by the tripeptide reduced glutathione, which produces a response at a concentration of 10(−5) M. 4. Although the SS2 is an endodermal system, the receptors involved in the response to food appear to be ectodermal. 5. The epithelium that lines the pharynx conducts SS1 pulses, but there is some evidence for polarization of conduction.

Excitatory Actions of Antho-RFamide, An Anthozoan Neuropeptide, on Muscles and Conducting Systems in the Sea Anemone Calliactis Parasitica

1987 ◽  
Vol 133 (1) ◽  
pp. 157-168 ◽  
Author(s):  
I. D. McFARLANE ◽  
D. GRAFF ◽  
C. J.P. GRIMMELIKHUIJZEN
Keyword(s):  
Electrical Activity ◽  
Slow Muscle ◽  
Conduction System ◽  
Sea Anemone ◽  
Sea Anemones ◽  
Nerve Net ◽  
Direct Excitation ◽  
Calliactis Parasitica ◽  
Muscle Groups ◽  
Fast Muscles

In the sea anemone Calliactis parasitica endodermal application of the anthozoan neuropeptide Antho-RFamide (<Glu-Gly-Arg-Phe-amide), at a concentration of 10−6 or 10−7moll−1, caused a long-lasting increase in tone, contraction frequency and contraction amplitude in several slow muscle groups but had no effect on contractions in fast muscles. The effects were investigated further in isolated muscle preparations. Ectodermal application to whole animals had no effect on muscle contractions. Both ectodermal and endodermal application, at 10−7moll−1, raised electrical activity in an ectodermal conduction system, the SSI, but had no effect on an endodermal conduction system, the SS2. Electrical activity in the SS2 was increased by application at 10−6moll−1 to the endoderm but not to the ectoderm. The peptide had no effect on the through-conducting nerve net. It is concluded that contractions evoked by Antho-RFamide may be partly due to neuronal activity, but probably also involve direct excitation of the muscles. The diverse excitatory actions of Antho-RFamide suggest that it may be a neurotransmitter or neuromodulator in sea anemones.

Quick and Slow Contractions in the Isolated Sphincter of the Sea Anemone, Calliactis Parasitica

1957 ◽  
Vol 34 (1) ◽  
pp. 11-28
Author(s):  
D. M. ROSS
Keyword(s):  
Latent Period ◽  
Spontaneous Activity ◽  
Neuromuscular Transmission ◽  
Sea Anemone ◽  
Optimal Frequency ◽  
Temporal Features ◽  
Calliactis Parasitica ◽  
Slow Contraction

1. The neuromuscular activities of isolated marginal sphincter preparations of the sea anemone, Calliactis parasitica, have been studied. They showed almost no rhythmical or spontaneous activity. 2. In addition to the facilitated step-like quick contractions in response to stimuli at frequencies between 0·2 and 3·0 sec., the preparations gave smooth slow contractions in response to stimuli (usually not less than 6 stimuli were necessary) at frequencies up to about 15 sec. (at 17-18°C.). These contractions are similar to those given by the so-called ‘slow’ muscles which do not take part in the quick closing movements of the animal. 3. A study was made of the relations between the size and latent period of the slow contraction and the number and frequency of stimuli delivered. At each frequency there is a threshold number of stimuli which only just gives a response; with additional stimuli the response gets bigger until a maximum is reached. There is an optimal frequency (stimuli about 6-8 sec. apart at ordinary temperatures) at which the biggest responses are obtained with fewest stimuli. 4. Certain mechanical and temporal features of the quick and slow contractions are compared and the observations are discussed in relation to current views on neuromuscular transmission and innervation in these and other invertebrates.

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