Comparative ultrastructural and cytochemical analysis of the cephalopod systemic heart and its innervation

Summary The present knowledge of the morphology of cephalopod central hearts is presented. The cytological characteristics of the epicardial, myocardial and endothelial tissue layers are reviewed. Myocardial cells are characterized as obliquely striated myocytes with a high level of oxidative metabolism. The voluminous myocardium is intensively penetrated by nerve fibers controlling the myogenic heart rhythm by different chemical transmitter systems. Catecholaminergic fluorophores and acetylcholinesterase activity could be localized by means of histochemical and cytochemical investigations. A glio-interstitial cell system is shown to be present in connection with nerve fibers and also uncombined between heart muscle cells. Its content of large different-sized inclusions is described and their function discussed.     

Cephalopod myocardial receptors: Pharmacological studies on the isolated heart ofSepia officinalis (L.)

Summary This paper presents a synopsis of the information available about the pharmacological action of various substances on the cephalopod heart, with special emphasis on the central heart ofSepia officinalis. Threshold concentrations, EC₅₀ values and maximum effective concentrations have been experimentally determined. Studies with various transmitter substances, analogous compounds and antagonists have led to the following picture: Acetylcholine is the natural inhibitory transmitter substance; it acts via receptors with nicotinic properties which can be blocked by d-tubocurarine and -bungarotoxin. The probable excitatory transmitter system is represented by a noradrenergic innervation. Noradrenaline has a positive inotropic and a positive chronotropic action on in vitro heart preparations. A positive inotropic response can also be evoked by serotonin (5-HT); this effect is not due to stimulation of the catecholamine receptor, as is shown by cross-over experiments with specific blocking agents. Furthermore, a peptidergic receptor system has been described which reacts with the molluscan cardioactive peptide FMRF amide most effectively. It is assumed that cardioactive peptides may reach the central heart in the circulating blood; the sites of synthesis and release are still unknown. Possibly the NSV-layer of the vena cava is involved in hormonal cardiovascular regulation processes.     

The peripheral innervation of the heart ofEledone moschata demonstrated by histofluorescence microscopy

Summary A fluorescence histochemical investigation of the cardiac nerves ofEledone moschata has demonstrated that they contain catecholamines. This suggests that the cephalopod heart is supplied by a double innervation, where cholinergic and aminergic mechanisms work antagonistically. This is similar to the vertebrate cardiac innervation and therefore represents a convergent evolution.     

An indirect demonstration of the substructure of the lamina basalis in the branchial heart of Sepia officinalis L. by means of cholinesterase reaction

Summary Using a cytochemical cholinesterase reaction, a filamentous substructure of the lamina basalis of the peripheral epithelium in the branchial heart of Sepia officinalis L. can be demonstrated. The reaction product can be identified between the probable collagenous microfilaments, so that a form of negative staining is given.This work was supported by the Deutsche Forschungsgemeingemeinschaft.     

A review of the electrophysiological,pharmacological and single channel properties of heart ventricle muscle cells in the snailLymnaea stagnalis

Although a considerable body of information has accumulated describing the pharmacological properties of a wide range of molluscan muscle types, the physiological bases underlying these properties have not been thoroughly investigated. At present, little is known about the types of ion channels and their regulation in molluscan muscle cell membranes. Voltage-clamp, and more recently, patch-clamp techniques have revealed molluscan muscles possess a complex array of channel types with various pharmacological and electrophysiological properties. The gating properties of these channels and their modulation by chemical agents, however, are still poorly understood. This review summarizes some aspects of molluscan muscle function with particular reference to the heart ventricle muscle of the pond snail,Lymnaea stagnalis.     

The part played by temperature in the rhythm of formation of markings on the shell of cuttlefish (Sepia officinalis L.) (Cephalopoda,Mollusca)

Résumé Le rythme de formation des stries d'accroissement de la coquille de seiche est fonction de la température. Il semble donc nécessaire d'en tenir compte avant de comparer divers Sepiidés (Age, Sous-espèces, etc.).     

Comparative study of the glycosidases of 2 Lepidoptera wood-eating Cossidae (Cossus cossus L., and Zeuzera pyrina L.) and various wood-eating Coleoptera]

The authors present here the results of their research concerning the study of the osidases of the caterpillars Cossus cossus L. and Zeuzera pyrina L. (Lepidoptera Cossidae). Its enzyme equipment shows very important differences compared to the different species of Scolytidae, Cerambycidae, Curculionidae and Buprestidae. The differences are lie especially in the absence of some osidases acting on polysaccharides (hémicelluloses and cellulose).     

Effects ofs-triazines on protein synthesis in leaves of peas (Pisum sativum L.) and sweet corn (Zea mays L.) and on the ultrastructure of pea cotyledons

Zusammenfassung Nachweis, dass die Blattbehandlung mit subletaler Konzentration von Simazin, Propazin, Igran und Prometon die Protein-Synthese bei Erbse und Mais vermehrt. Die Blattbehandlung mit Simazin zerstörte die Ultrastruktur des Samenlappens bei der Erbse.

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This study was supported by the Agriculture Research Service, USDA, Grant No. 12-14-100-9903, administered by the Human Nutrition Division, Beltsville, Maryland.     

Use of the isolated heart of a freshwater mussel (Anodonta cygnea L.) for biological estimation of 5-hydroxytryptamine

Zusammenfassung Die rhythmischen Kontraktionen des isolierten Herzventrikels vonAnodonta werden von 5-Hydroxy-Tryptamin niedriger Konzentration beschleunigt und verstärkt. Adrenalin, Noradrenalin, Histamin, Acetylcholin, Tyramin usw, wesentlich höherer Konzentrationen haben keine oder nur geringe Wirkungen. DasAnodonta-Herz-Präparat scheint deshalb für den biologischen Nachweis von 5-Hydroxy-Tryptamin (Serotonin, Enteramin) geeignet.

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Aided by a grant from the Kungl. Fysiogr. Sällsk., Lund.     

Comparative evaluation of 7 helminth antigens in the enzyme-linked immunosorbent assay (E.L.I.S.A.)

Summary 112 sera from Europeans with parasitologically proven helminthiasis were tested in the enzyme-linked immunosorbent assay (E.L.I.S.A.) against 6 crude extracts of various helminths (2 of adult worms:Dipetalonema viteae, Fasciola hepatica; 3 of eggs:Ascaris suum, Toxocara canis, Schistosoma mansoni; and ofEchinococcus granulosus scolices) and against bovine hydatid fluid. Each serum was tested simultaneously at a fixed dilution of 1:160 against all antigens. Extensive cross-reactions were observed, leading to the conclusion that non-purified helminth antigens, even in combination, are of limited value for reliable serodiagnosis in E.L.I.S.A.     

Coeloconic sensilla on the antennae of the yellow fever mosquito,Aedes aegypti (L.)

Zusammenfassung Elektronenoptischer Nachweis von Sensilla coeloconica beiAedes aegypti-«Weibchen» was beweist, dass nicht nur Culicinae, sondern auch Anophelinae Sinnesstrukturen besitzen.

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Supported by Medical Research Council Grant No. MA 2909.