scholarly journals Ultrastructural Localization of Antho-RWamides I and II at Neuromuscular Synapses in the Gastrodermis and Oral Sphincter Muscle of the Sea Anemone Calliactis parasitica

1995 ◽  
Vol 189 (3) ◽  
pp. 280-287 ◽  
Author(s):  
J. A. Westfall ◽  
K. L. Sayyar ◽  
C. F. Elliott ◽  
C. J. P. Grimmelikhuijzen
Keyword(s):  
Ultrastructural Localization ◽  
Sea Anemone ◽  
Sphincter Muscle ◽  
Neuromuscular Synapses ◽  
Calliactis Parasitica

Effects of three anthozoan neuropeptides, Antho-RWamide I, Antho-RWamide II and Antho-RFamide, on slow muscles from sea anemones

1991 ◽  
Vol 156 (1) ◽  
pp. 419-431 ◽  
Author(s):  
I. D. McFarlane ◽  
P. A. Anderson ◽  
C. J. Grimmelikhuijzen
Keyword(s):  
Smooth Muscle ◽  
Body Wall ◽  
Threshold Concentration ◽  
Sphincter Muscle ◽  
Sea Anemones ◽  
Nerve Net ◽  
Neuromuscular Synapses ◽  
Calliactis Parasitica ◽  
Body Wall Muscles ◽  
Evoked Contractions

Antho-RWamide I (less than Glu-Ser-Leu-Arg-Trp-NH2) and Antho-RWamide II (less than Glu-Gly-Leu-Arg-Trp-NH2), the second and third anthozoan neuropeptides to be identified, both induced slow contractions of several endodermal muscles in four species of sea anemone. In a fifth species, Protanthea simplex, Antho-RWamide II, but not Antho-RWamide I, evoked contractions of body wall muscles. Isolated, trimmed sphincter muscle preparations of Calliactis parasitica contracted at a threshold concentration of 10(−9) mol l-1 Antho-RWamide II. Antho-RWamide II was more potent than Antho-RWamide I. Unlike the responses to Antho-RFamide (the first anthozoan neuropeptide described), these were simple contractions with no change in spontaneous activity. The Antho-RWamides did not excite electrical activity in any of the three known conducting systems (the through-conducting nerve net and the slow systems 1 and 2), indicating that they may be acting directly on endodermal muscles. Application of peptides to smooth muscle cells, isolated from the sphincter of C. parasitica, confirmed that Antho-RWamide I and II act directly on the muscle. We conclude that the Antho-RWamides may be neurotransmitters at some neuromuscular synapses in sea anemones.

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.

Sign in / Sign up

Export Citation Format

Share Document