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Journal of Experimental Biology 37,732-752 (1960)
Published by Company of Biologists 1960

The Effects of Ions and Drugs on Neuromuscular Preparations of Sea Anemones : I. On Preparations of the Column of Calliactis and Metridium

D. M. ROSS ¹

¹ Department of Zoology, University College London; Department of Zoology, University of Alberta, Edmonton, Alberta, Canada

1. Isolated preparations of the columns of Calliactis and Metridium take up a basic extended length and show repeated contractions at intervals of a few minutes to half an hour. The preparations respond to stimuli with slow movements whose latencies range from about 20 sec. to 2 min.

2. Direct contractions and higher tonus of the preparations are caused by excess K⁺ and by Mg²⁺-free sea water; excess -Ca²⁺ raises tone slightly.

3. Activity is greatly enhanced by Mg²⁺-free water, and moderately enhanced by excess K⁺ and excess Ca²⁺. It is abolished by excess Mg²⁺ and Ca²⁺-free sea water, but not by sea water free of both Ca²⁺ and Mg²⁺. In K⁺-free sea water and in Na⁺-free sea water activity declines slowly and responses to stimuli still occur for at least 1 hr.

4. Except for some enhancement by excess Ca²⁺ and the depression with excess Mg²⁺ and Ca²⁺-free sea water, responses to stimuli are not much affected by ions.

5. Acetylcholine and associated drugs, and also histamine, 5-hydroxytryptamine, and many other substances, have no significant effects on the tone, activity, or responses of column preparations.

6. Adrenaline raises tonus at a concentration of 1 x 10^-6; at 1 x 10^-5 and above; it causes direct contractions, enhanced activity and high tonus, but it has no effect on responses to stimuli. Noradrenaline, dopamine, tyramine, and other related compounds, as well as various adrenergic blocking agents, are totally inactive.

7. Tryptamine, at concentrations of 1 x 10^-4, causes direct contractions, high tonus and enhanced responses to stimulation. 5-Methoxytryptamine has similar effects.

8. To be effective, treatments must be applied directly to the contractile part of the preparation. Applying the active ions and drugs to attached strips of column has no effect.

9. Some comparative and functional aspects of the results are discussed.