Summary
The neuromuscular junctions in the crayfish heart were studied with the electron microscope and were classified into two types based on the characteristics of the post-synaptic side. Type I junction was characterized by a mazy post-synaptic apparatus which has been referred to in this work as the junctional envelope, consisting of the cytoplasmic processes and/or lamellae of the muscle cell. Type II junction on the other hand, lacked the junctional envelope. The nerve terminals in both Type I and Type II junctions contained two types of synaptic vesicles: large granular and small agranular vesicles, which were about 1000 Å and 450 Å in diameter respectively. The physiological significance of these neuromuscular junctions and the nature of their synaptic vesicles are discussed.
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References
Alexandrowicz, J. S.: The innervation of the heart of the Crustacea. I. Decapoda. Quart. J. micr. Sci. 75, 182–249 (1932).
Burnstock, G., Robinson, P. M.: Localization of catecholamines and acetylcholinesterase in autonomic nerves. Circulat. Res. 21, Suppl. III, 43–55 (1967).
Cook, B. J.: An investigation of factor S, a neuromuscular excitatory substance from insects and crustacea. Biol. Bull. 133, 526–538 (1967).
De Robertis, E. D., Iraldi, A. P. de: Plurivesicular secretory processes and nerve endings in the pineal gland of the rat. J. biophys. biochem. Cytol. 10, 361–372 (1961).
Edwards, G. A.: The fine structure of a multiterminal innervation of an insect muscle. J. biophys. biochem. Cytol. 5, 251–244 (1959).
—, Ruska, H., Harven, E. de: Electron microscopy of peripheral nerves and neuromuscular junctions in the wasp leg. J. biophys. biochem. Cytol. 4, 107–114 (1958a).
Florey, E.: Studies on the nervous regulation of the heart beat in decapod crustacea. J. gen. Physiol. 43, 1061–1081 (1960b).
Hámori, J.: Innervation of insect leg muscle. Acta biol. Acad. Sci. hung. 12, 219–230 (1961b).
Horridge, G. A.: Arthropoda; Nervous control of effector organs. In: Structure and function in the nervous system of invertebrates, vol II (T. H. Bullock, G. A. Horridge, eds.), p. 965–1004. San Francisco and London: W. H. Freeman and Company 1965.
—, Bullock, T. H.: Comparative microanatomy of nervous elements. In: Structure and function in the nervous systems of invertebrates, vol. I (T. H. Bullock, and G. A. Horridge, eds.), p. 35–121. San Francisco and London: W. H. Freeman and Company, 1965.
Irisawa, A., Hama, K.: Some observation on the fine structure of the mantis shrimp heart. Z. Zellforsch. 68, 678–688 (1965).
Kloot, W. G. van der: Factor S-a substance which excites crustacean muscle. J. Neurochem. 5, 245–252 (1960).
Komuro, T.: The fine structure of the cardiac muscle of the crayfish with special reference to the neuro-muscular junction. J. electron microscopy 17, 273 (1968).
Krijgsman, B. J.: Contractile and pacemaker mechanism of the heart of arthropods. Biol. Rev. 27, 320–346 (1952).
Luft, J. H.: Improvements in epoxy resin embedding methods. J. biophys. biochem. Cytol. 9, 409–414 (1961).
Maynard, D. M.: Activity in a crustacean ganglion. 1. Cardio-inhibition and acceleration in Panulirus argus. Biol. Bull, Woods Hole 104, 156–170 (1953a).
Millonig, G.: A modified procedure for lead staining of thin sections. J. biophys. biochem. Cytol. 11, 736–739 (1961).
Nadol, J. J. R., Darin de Lorenzo, A. J.: Observations on the fine structure of associated axo-dendritic synapses and neuromuscular junctions in Homarus. J. comp. Neurol. 132, 419–444 (1968).
Ostlund, E.: The distribution of catecholamines in lower animals and their effect on the heart. Acta physiol. scand. 31, Suppl. 12, 1–67 (1954).
Peterson, R. P., Pepe, F. A.: The fine structure of inhibitory synapses in the crayfish. J. biophys. biochem. Cytol. 11, 157–169 (1961).
Prosser, C. L.: Circulation of body fluids. In: Comparative animal physiology, 2nd ed. (C. L. Prosser and F. A. Brown, eds.), p. 386–416. Philadelphia: Saunders 1962.
Sabatini, D. D., Bensch, K., Barrnett, R. S.: Cytochemistry and electron microscopy. The preservation of cellular ultrastructure and enzymatic activity by aldehyde fixation. J. Cell Biol. 17, 19–58 (1963).
Uchizono, K.: Morphological background of excitation and inhibition at synapses. J. electron microscopy 17, 55–66 (1968).
Welsh, J. H.: Chemical mediation in crustaceans. II. The action of acetylcholine and adrenalin on the isolated heart of Panulirus argus. Physiol. Zool. 12, 231–237 (1939).
Wiersma, C. A. G., Novitski, E.: The mechanism of the nervous regulation of the crayfish heart. J. exp. Biol. 19, 255–265 (1942).
Wolfe, D. E., Potter, L. T., Richardson, K. C., Axelrod, J.: Localizing tritiated norepinephrine in sympathetic axons by electron-microscopy and autoradiography. Science 138, 440 (1962).
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Acknowledgement. The author wishes to express sincere gratitude to Prof. T.Yamamoto for the kind encouragement and guidance during the course of this study.
The presence of this unusual neuromuscular junction, coupled with the histological characteristics of heart muscles themselves (Komuro, 1968), may be involved in the different physiological properties of the crustacean heart. This subject will be discussed in a later publication by the author.
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Komuro, T. Unusual neuromuscular junctions in the heart of the crayfish (Procambarus clarkii). Z. Zellforsch. 105, 317–324 (1970). https://doi.org/10.1007/BF00335459
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DOI: https://doi.org/10.1007/BF00335459