European Society for Comparative Physiology and Biochemistry Third Congress Organizing Committee: A. D. F. ADDINK, President Animal Physiology, Gorlaeus Laboratory, Rijksuniversiteit Leiden C. M. BALLINTIJN Zoological Laboratory, Rijksuniversiteit Groningen A. P. VAN OVERBEEKE Zoological Laboratory, Katholieke Universiteit Nijmegen L. M. SCHCHDNHOVEN Animal Physiology, Landbouw Hogeschool Wageningen N. SPRONK, Secretary Biological Laboratory, Vrije Universiteit Amsterdam D, I. ZANDEE Chemical Animal Physiology, Rijksuniversiteit Utrecht Sponsors: The Commission of the European Community Ministerie van Landbouw en Visserij Technische Hogeschool Delft Technische Hogeschool Twente Landbouwhogeschool Wageningen Rijksuniversiteit Leiden Rijksuniversiteit Utrecht Universiteit van Amsterdam Vrije Universiteit Proceedings of the Third Congress of the European Society for Comparative Physiology and Biochemistry, August 31-September 3, 1981, Noordwijkerhout, Netherlands Exogenous and Endogenous Influences on Metabolic and Neural Control of • RESPIRATON • FEEDING • ACTIVITY AND ENERGY SUPPLY IN MUSCLES • ION- AND OSMOREGULATION • REPRODUCTION • PERCEPTION AND ORIENTATION Volume 2 Abstracts Editors A. D. F. ADDINK Animal Physiology Gorlaeus Laboratory Rijksuniversiteit Leiden, Netherlands N. SPRONK Biological Laboratory Vrije Universiteit, Amsterdam, Netherlands PERGAMON PRESS OXFORD · NEW YORK · TORONTO · SYDNEY • PARIS · FRANKFURT U.K. Pergamon Press Ltd., Headington Hill Hall, Oxford OX3 OBW, England U.S.A. Pergamon Press Inc., Maxwell House, Fairview Park, Elmsford, New York 10523, U.S.A. CANADA Pergamon Press Canada Ltd., Suite 104, 150 Consumers Road, Willowdale, Ontario M2J 1P9, Canada AUSTRAUA Pergamon Press (Aust.) Pty. Ltd., P.O. Box 544, Potts Point, N.S.W. 2011, Australia FRANCE Pergamon Press SARL, 24 rue des Ecoles, 75240 Paris, Cedex 05, France FEDERAL REPUBLIC Pergamon Press GmbH, 6242 Kronberg-Taunus, OF GERMANY Hammerweg 6, Federal Republic of Germany Copyright © 1982 Pergamon Press Ltd. All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means: electronic, electrostatic, magnetic tape, mechanical, photocopying, recording or otherwise, without permission in writing from the publishers. First edition 1982 Library of Congress Cataloging in Publication Data European Society for Comparative Physiology and Biochemistry. Congress (3rd: 1981: Noordwijkerhout, Netherlands) Exogenous and endogenous influences on metabolic & neural control of respiration, feeding, activity and energy supply in muscles, ion- and osmoregulation, reproduction, perception and orientation. Includes indexes. Contents: v. 1. Invited lectures — v. 2. Abstracts. I. Metabolic regulation—Congresses. '2. Neurotrophic functions—Congresses. 3. Bio­ logical control systems—Congresses. I. Addink, A. D. F. (Alberti Daniel Franςois), 1935- II. Spronk, N. III. Title. QP171.E97 1981 591.1'88 82-3657 AACR2 British Library Cataloguing in Publication Data European Society for Comparative Physiology and Biochemistry. Congress (3rd: 1981: Noordwijkerhout) Exogenous and endogenous influences on metabolic & neural control. Vol. 2: Abstracts 1. Physiology, Comparative—Congresses I. Title II. Addink, A. D. F. III. Spronk, N. 574.1 QPl ISBN 0-08-027986-4 (vol. 1) ISBN 0-08-028845-6 (vol. 2) In order to make this volume available as economically and as rapidly as possible the authors' typescripts have been reproduced in their original forms. This method unfortunately has its typographical limitations but it is hoped that they in no way distract the reader. Printed in Great Britain by A. Wheaton & Co. Ltd., Exeter Sponsors The Commission of the European Community The Ministerie van Onderwijs en Wetenschappen Technische Hogeschool Delft Technische Hogeschool Twente Landbouw Hogeschool Wageningen Rijksuniversiteit Leiden Advertisers Canberra-Positronika Eindhoven Congress Centre Leeuwenhorst Noordwijkerhout Elsevier Publishing Amsterdam Baker Chemicals Deventer K.L.M. Amstelveen Setaram Lyon Radiochemical Centre Amersham (U.K.) E.L.G.A. Griesheim (B.R.D.) Pergamon Press Oxford This volume is a collection of the abstracts from both invited lectures and posters related to the subjects of the conference. The Organizing Committee of the Conference and the editors have allowed the authors full latitude to express their views, which remain their entire responsibility. Sponsors The Commission of the European Community The Ministerie van Onderwijs en Wetenschappen Technische Hogeschool Delft Technische Hogeschool Twente Landbouw Hogeschool Wageningen Rijksuniversiteit Leiden Advertisers Canberra-Positronika Eindhoven Congress Centre Leeuwenhorst Noordwijkerhout Elsevier Publishing Amsterdam Baker Chemicals Deventer K.L.M. Amstelveen Setaram Lyon Radiochemical Centre Amersham (U.K.) E.L.G.A. Griesheim (B.R.D.) Pergamon Press Oxford This volume is a collection of the abstracts from both invited lectures and posters related to the subjects of the conference. The Organizing Committee of the Conference and the editors have allowed the authors full latitude to express their views, which remain their entire responsibility. LECTURES FOOD SELECTION AND REGULATION OF FOOD INTAKE IN INVERTEBRATES R.F. CHAPMAN Centre for Overseas Pest Research, College House, Wrights Lane, London W8 5SJ, UK In most invertebrates feeding is a discontinuous process which is initiated by stimuli arising from the external environment. Only in molluscs and insects have comprehensive studies of food selection and the control of food intake been undertaken and most attention has been devoted to predaceous and phytophagous species. Only phytophagous terrestrial species will be discussed. Food selection may involve a distance component and in predators vision is important together with morphological adaptations which permit the prey to be caught without approaching very closely. Olfactory selection may involve specific odours, as in many beetles, or be unspecific. On contact, the chemical and physical properties of the food are important. Selectivity may be modified by the immediate previous experience of the organism, such as deprivation of food and water, influencing its physiological state, and, in the longer term, by learning, of which food aversion learning is the best known. In phytophagous species food intake is driven by phagostimulatory chemicals, and physiological adaptation of the sense-organs associated with feeding may be minimised by behavioural adaptations, but can contribute to the cessation of feeding. In many cases, however, the size of a meal is determined principally by volumetric feedback from the gut and body wall. Humoral changes, themselves a consequence of feeding, add to the volumetric effects through the central nervous and peripheral nervous systems. FOOD SELECTION AND THE REGULATION OF BODY ENERGY IN VERTEBRATES J. LE MAGNEN Laboratoire de Neurophysiologie Sensorielle et Comportementale, College de France, 11, Place Marcelin Berthelot, 75231 Paris Cedex 05 Contrary to oxygen supply which is dependent, moment to moment, on breathing, the continuous supply of nutrients to tissues is provided from endogenous energy store. Feeding behaviour is periodically activated. This activation or "stimu­ lation to eat" is primarily due to the depletion of a short-term energy store, the meal, and to a correlated fall of the blood glucose level. This prandial period­ icity is demonstrated to be accelerated by the repletion and suppressed by the depletion of fat stores. In various vertebrate species, a changing and programmed level of maximal repletion and depletion of body fats generates diurnal or sea­ sonal rhythms of lipogenesis and hyperphagia balanced by a subsequent lipolysis and hypophagia. The neuroendocrine bases for such short or long term regulation of body energy balance now elucidated are described. In addition blood borne systemic signals, a sensory stimulation of eating or no eating and the palatability of foods are involved in a regulatory food selec­ tion, and in the control of meal sizes. From a genetic background of innate food preferences and aversions, which appear species specific, the palatability of food is learned. The survival and selective value of overall mechanisms which, through food intake, controls the body energy balance and body composition, is emphasized. THIRST AND THE REGULATION OF HYDROMINERAL BALANCE S. NICOLAIDIS Laboratoire de Neurobiologie des Regulations C.N.R.S. - College de France 11 place Marcel in Berthelot-75231 PARIS Cedex 05 The onset or the termination of drinking is essentially under the control of specific stimuli acting upon specific receptors projecting to specific centers from which the behavior originates. This physiological control of drinking does not imply that drinking cannot be initiated without the action of the physiolo­ gical stimuli. We will review successively the regulatory or primary drinking, i.e. drinking under the control of physiological stimulations, and non-regulatory drinking, i.e. drinking which happens independently from physiological stimula­ tions of the internal milieu. Intracellular (IC) dehydration normally occurs following water losses from the various physiological routes. Such losses result in an electrolytic and particularly Na+ hyperconcentration of the extracellular (EC) space and therefore pulling water out from the IC milieu. This cellular partial emptying brings about membrane shrinkage resulting in membrane potential and excitability changes. This is how the cellular dehydration transducer may work at the receptorsΊevel. How­ ever a sodium receptive mechanism, transducing the EC Na"*" excess in terms of electric message cannot be ruled out. EC dehydration tends to occur when both water and sodium losses occur simul­ taneously, so maintaining normal ionic concentration and cellular volume. In this case, both the vascular ant the interstitial spaces are depleted. This is why EC thirst is often referred to as hypovolemic thirst. It typically happens following isotonic losses such as hemorrage, diarrhea or experimental injection of a colloid (polyethylene glycol) which sequesters a fraction of isotonic solution within the organism. Primary drinking can be elicited following the stimulation of 2 types of receptors sensing the deficits of the corresponding 2 hydrational spaces, i.e. the IC and the EC space. These receptors seem to project on regulatory diencephalic areas eliciting the appropriate responses of drinking in addition to responses of excretion including diuresis, anti-diuresis and sweating and to interspace water and electrolytes movements affecting blood volume and pressure. The IC receptors are localized in several diencephalic areas and also in the portal hepatic bed. They seem to be more or less intermingled with the so-called centers of drinking behavior. The EC space receptors were found in appropriate areas of the vascular space such as the low pressure big vessels of the left atrium. Today, we know that there are receptors around the thin walled sinus of the circumventricular organs and probably around the cerebroventricular walls. The receptors of the EC space seem to be affected by the dipsogenic hormone angiotensin II (All) whether it comes from the kidney-born renin or the brain tissue-born isorenin. The combined action of direct EC stimulations and the effect of All seem to be achieved by means of a convenient phenomenon able to integrate at the receptor level both stimulations accounting for the EC depletion. This phenomenon seems to be the reduction of the size of specific vascular and para­ vascular structures sensed by mechano-receptive elements. I.e. either volemia or isotonic depletion passively deflate the recipients,although All actively reduces the same recipients>volume by acting upon contractile elements. The fact that EC receptors are independent from IC depletion receptors accounts for the additi- vity of IC and various EC stimulations. Once various synergic stimulations have reached the threshold of drinking they trigger the appropriate oriented and specific arousal leading the animal towards water consumption unless other contradictory needs divert the animal from this behavior. Water consumption itself is enhanced by the insentives of the oral area. Extero-receptors of this oral area in addition to those of the larynx, oesophagus and gastro-intestinal areas project on diencephalic units in order to announce and compute the amount consumed during the act of drinking and therefore in order to end its consumption at the appropriate moment. Research on the hypo­ thalamic mechanism of interaction of the above messages with various physiological stimuli, and on the other brain areas which are implicated in the regulatory responses of drinking, of diuresis or sweating and of hemodynamic responses has made rapid progress and will be looked at in different chapters of the review. COMPARATIVE ASPECTS OF DIGESTION IN NONRUMINANT HERBIVORES H.HÜRNICKE Universitat Hohenheim - D 7000 Stuttgart 70 About half of the more than 4000 living mammalian species are herbi­ vorous in the sense that they predominantly feed on products of plant origin. The usual classification of diet types (frugivor, herbivor, folivor, granivor, nectarivor, pollenivor, tuberivor) is rather artifical since the mayority of animals show greater diversi­ fication in their dietary habits. The food selected varies also with age» season, reproductive state, competitive pressure etc. Only few species are highly specialized (oligo- or monophagy)· Allometric con­ siderations have to be taken into account. Seed-eating prevails among the smallest mammals, leaf-eating is predominant in medium sized, and grasseating in larger animals. Ingestion pattern and di­ gestive processes must be seen in relation to the necessity of the animal to deal with toxic secondary plant compounds. Structure and function of the gastrointestinal tract can partly be related to texture, energy density and fibre content of the diet. Many peculiarities of gastrointestinal structure are not yet suffi­ ciently understood because functional studies are lacking. Some of the larger herbivores have elaborated stomach sacculations and a certain degree of gastric fermentation. In many rodents, large areas of the stomach are covered by squamous epithelium, sometimes re­ ducing the glandular part to a small disk. Function of this stomach type may be rather that of storage than that of a fermentation chamber. Total intestinal length, and the fraction occupied by the caecum increase with dietary fibre content. The energy of cellulose can partly be utilized by hind-gut fermentation and by direct ab­ sorption of the resulting volatile fatty acids. In contrast, sub­ stantial amounts of the bacterial protein and the vitamins synthe­ sized by caecal fermentation can only be utilized when faecal rein- gestion takes place.