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Morphology, ultrastructure and contractile properties of muscles responsible for superior tentacle movements of the snail

Krajcs, Nóra and Márk, L. and Elekes, K. and Kiss, T. (2012) Morphology, ultrastructure and contractile properties of muscles responsible for superior tentacle movements of the snail. Acta Biologica Hungarica, 63 (Supple). pp. 129-140. ISSN 0236-5383

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Abstract

Bending, twitching and quivering are different types of tentacle movements observed during olfactory orientation of the snail. Three recently discovered special muscles, spanning along the length of superior tentacles from the tip to the base, seem to be responsible for the execution of these movements. In this study we have investigated the ultrastructure, contractile properties and protein composition of these muscles. Our ultrastructural studies show that smooth muscle fibers are loosely embedded in a collagen matrix and they are coupled with long sarcolemma protrusions. The muscle fibers apparently lack organized SR and transverse tubular system. Instead subsarcolemmal vesicles and mitochondria have been shown to be possible Ca<sup>2+</sup> pools for contraction. It was shown that external Ca<sup>2+</sup> is required for contraction elicited by high (40 mM) K<sup>+</sup> or 10<sup>−4</sup> M ACh. Caffeine (5 mM) induced contraction in Ca<sup>2+</sup>-free solution suggesting the presence of a substantial intracellular Ca<sup>2+</sup> pool. High-resolution electrophoretic analysis of columellar and tentacular muscles did not reveal differences in major contractile proteins, such as actin, myosin and paramyosin. Differences were observed however in several bands representing presumably regulatory enzymes. It is concluded that, the ultrastructural, biochemical and contractile properties of the string muscles support their special physiological function.

Item Type: Article
Subjects: Q Science / természettudomány > QH Natural history / természetrajz
Depositing User: Ágnes Sallai
Date Deposited: 12 Jan 2018 09:55
Last Modified: 12 Jan 2018 09:55
URI: http://real.mtak.hu/id/eprint/72420

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