7he E j e c t s of Some Hormones of the Heart of a Fresh-Water Mud-Eel 25 1

on the concentration of several substrates in serum and liver provided additional diagnostic criteria to differentiate between N i and Fe deficiency. During Ni defi- ciency thc concentrations of the energy carriers triglycerides, glycogen and glucose were r.educed by 40, 60 and 90 O / o , respectively. During Fe deficiency, however, only the concentration of the triglycerides was lowered and this by 49 o/o. The contents of adenosine-5'-triphosphate, urea and cholesterol in the liver were not reduced during Fe deficiency nor were they during Ni deficiency.

Literatur

1. FAWCETT, J. K.; SCOTT, J. E., 1960: J. d in . Pathol. 13, 156. 2. KIRCHGESSNER, M.; SCHNEGG, A,, 1976: Bioinorganic Chemistry 6, 155. 3. I<IRCHGESSNER, M.; SCHNEGG, A,: in Vorbereitung. 4. NIELSEN. F. H.: MYRON. D. R.: GIVAND. s. H.: Z I M M E R M A N N . T. 1.: OLLERICH. D. A., . " .

1975: J .Nu t r . 105, 1620.' 5. SCHNEGG, A.; KIRCHGESSNER, M., 1975: 2. Tierphysiol., Tierernahrg. u. Futtermittelkde.

36. 63. - -, -- - 6. S c m w x , A.; KIRCHGESSNER, M., 1975: Nutr. Metabol. 19, 268. 7. SCHNEGG, A.; KIRCHGESSNER, M., 1976: Arch. Tierernahrung 26, 543. 8. SCHNEGG, A.; KIRCHGESSNER, M., 1976: Internat. 2. Vit. Ern. Forschung 46, 96. 9. SCHNEGG, A.; KIRCHGESSNER, M., 1977: Zentr. Vet. Med. A 24, 242.

10. SCHNEGG, A,; KIRCHGESSNER, M., 1977: 2. Tierphysiol., Tierernahrg. u. Futtermittelkde.

11. WATSON, D., 1960: Clin. chim. Acta 5, 637. 30, 200.

AnschriP der Autoren: Institut fur Ernahrungsphysiologie der T U Munchen, 8050 Freising-Weihenstephan

Post-Graduate Department of Zoology, Bhagalpur University, India and Department of Physiology Bhagalpur Medical College, India

The Effects of Some Hormones and Cations on the Force and Rate of Contraction of the Heart of a Fresh-Water Mud-Eel

Amphipnous cuchia (Ham.)

By NARENDRA MISHRA, JAGDISH OJHA, DEEP NARAIN DUBE and JYOTI SWAROOP DATTA MUNSHI

Receipt of M s . 12 .9 . 1977

Introduction

The Indian mud-eel, Amphipnous cucbia, is an obligatory air breather, which inhabits the muddy banks of marshes and slow running rivers of fresh and brackish waters of India, Pakistan, Bangladesh and Burma. In the torrid seasons, the ambient waters evaporate and A. cucbia escapes desiccation by burrowing into the mud. Though Amphipnous cuchia is adapted to extreme drought conditions, nevertheless water

2. Tierphysiirl., T i e r c r n l h r g . u. Futrermi t te lkde . 39 (1977), 251-257 h .---I..^ .* I .. . - .. . . _ ..

252 Mishra e t al.

remains its primary medium for normal metabolism. Recent studies on the control of breathing in this mud-eel suggest that this fish has retained the piscine mechanism of ventilating the rudimentary gills with water (LOMHOLT and JOHANSEN 1974).

The morphology and anatomy of air-breathing organs of Amphipnous cuchia has been worked out by MUNSHI and SINGH (1968) and HUGHES and MUNSHI (1973). According to them the gills of A . cuchia are greatly reduced except a few coarse filaments on the second arch. Aquatic respiration through skin is supplemented by aerial respiration through a pair of air-sacs on lateral sides of the head.

MUNSHI and MISHRA (1974) have studied in detail the niorphological structure of the heart of Amphipnous. The present investigation on the effects of certain hormones and ions on the heart of Amphipnous cuchia has been undertaken for evaluating its function.

Materials and methods

Adult healthy specimens of Amphipnous cuchia were col1cc:ed from the Fonds and swamps of Alaninagar (Saharsa, Bihar) and were kept in aquaria in the laboratory. Th,e fish were stunned by blow on the head and then pithed by means of a needle. T h e heart was exposed and cannulated with a frog-heart canula and was attqched with a Starling’s heart lever. During th.e experiment, the intact heart was maintained in Ringer’s solution. 5 nil Ringer’s solution was poured on the heart a t regular inter- vals of 30-50 seconds. All effects were recorded on a kyniograph.

T h e hormones used were Adrenaline (10 pg/nil), Acetylcholine (5 pg/ml), Atropine (10 pg/ml), Reserpine (Serpacil) (0.1 mg/ml) and oxytocin. The concentrated solu- tions of the chloride salts of sodium, potassium and calcium were used. Besides this cold and hot ringers were also used. The experiments were performed a t 31.5OC 2 1 o c .

Results

Effect of Acetylcholine

Acetylcholine slowed the cuchia’s heart. Concentrations of acetylcholine from 1 to 10 pg/ml produced the same result.

Fig. 1. Positive chronotropic and inotropic effect of Atropine

The Effects of Some Hormones of the Heart of a Fresh-Water Mud-Eel

Effect of Atropine

253

Atropine had pronounced effect on the heart-beat and force of contraction of th,e heart of A. crtchia. The frequency and the force of contraction increased (see Fig. 1).

Effect of Adrenaline

From thc Fig. 2 it is evident that the application of adrenaline on the heart causes increase i n the rate (positive chronotropic) and force of the contraction of thc heart (positive inotropic).

F i g . 2: Positive chronotropic and inotropic effect of Adrenaline and negative chronotropic and inotropic effect of acetylcholine

. I NORMAL SERPACIL

F i g . 3. Negative chronotropic and ino- tropic effect of Reserpine (Serpacil)

I NORMAL

Fig. 4 . Action of Oxytocin

Effect of Reserpine (Serpacil)

It decreases both the force of contraction and heart reate (Fig. 3).

Effect of Oxytocin

I n the case of oxytocin, it was observed that af- ter an initial decrease there is an increase in the amplitude of con- traction (see Fig. 4).

Effect of ions

Generally high Naf- ion concentration stimulates the heart slightly but after an initial increase in the amplitude of con- traction a decrease was observed. High Kf- ion concentration had the same effect as sodium, but Ca++ had a nega- tive chronotropic and inotropic effect (see Figs. 5 a and b).

254 Mishra e t al.

a

Fig. Sa and rb. Action of Ca++ and 1C+-ion

Effect of Hot and Cold ringer

Hot ringer’s (38O C) produced positive chronotropic and inotropic effect whereas cold ringer (05’ C) produced a negativ.e chronotropic and inotropic effect (Fig. 6).

.

Fig . 6. Effect of hot and cold Ringer’s solution

Discussion

Earlier MOTT (1957) has sumniarised the effects of hormones i. e. Adrenaline, Nor- adrenaline, Atropine, Acetylcholine, Histamine and pituitary extract on intact and isolated heart of Elasmobranch and Teleost fish.

7 h e Effects of Some Hormones of the Heart of a Fresh-Water Mud-Eel 255

In fish, the changes in the cardiac output are usually associated with changes in stroke volume accompanied by some adjustment of heart-rate (RANDALL 1968). In most fish the rat,e-changes are mediated via the cholinergic nerve innervating the heart, changes in temperature and changes in the level of circulating catecholamines (RANDALL 1970).

T h e application of acetylcholine has a negative chronotropic effect and it has been assumed that cardiac vagus contains cholinergic fibres (RANDALL 1966). The present investigation corroborates the earlier findings by RANDALL (1966), FALK et al. (1966) and HATTING (1974). W e found that acetylcholine also produces a negative inotropic effect but HATTING (1974) has reported a positive inotropic effect.

Catecholamines are known to increase both the rate (positive chronotropic) and myocardial contractility (positive inotropic effect) of the mammalian heart. Both the positive inotropic and chronotropic responses result from the action of catechola- mines on p-adrenargic receptor sites in the heart (RANDALL 1970). Both adrenaline and nor-adrenaline increase ventral and dorsal aortic blood-pressure and may either increase, decrease or have no effect on heart rate when injected into the intact fish (RANDALL and STEVENS 1967 and RANDALL 1970).

Generally direct effect of catecholamines on the heart is stimulating. Normally the adrenaline has a positive chronotropic and inotropic effect on teleostean heart (FAI,K et nl. 1966). The present investigation is in agreement with this generalization.

Atropinization increases heart rate in both Elasmobranchs ( JOHANSEN et al. 1966) and teleosts (RANDALL 1966), blocking the effect activity in cholinergic fibres inner- vating the heart. In A . cuchia also atropine has a positive chronotropic effect.

There i s little data on the eff,ect of Reserpine (Serpacil) on the heart of the teleost fish but i n lamprey and hagfish hearts Reserpine (Serpacil) depletes the catechola- mines stores (BLOOM et al. 1961) and causes a loss in vigour in the heart which can be restored by adrenaline (CHAPMAN et al. 1963). In the present investigation we find that it decreaes both the forces of contraction and rate. Thus we conclude that it has a negative chronotropic and inotropic effect on heart of this fish.

I(1TCHIN et al. (1959) have reported direct relaxing effect of oxytocin on vascular smooth muscle of man. They also observed a decrease in systolic and diastolic blood pressure followed by increase in limb blood flow. A reflexly induced tachycardia and increase i n cardiac output accompany the depressor phase. The vasodilator effect of oxytocin is independent of autonomic receptors (GOODMAN and GILMAN 1970).

The ncuro-hypophysial hormones oxytocin and vasopressin cause prolonged and marked rise in ventral aortic blood pressure but they have little effect on the dorsal aortic blood pressure in the eel (RANDALL 1970).

In the present investigation we find that after an initial decrease in rate, oxytocin stiniulated an increased rate. This shows that it has a positive chronotropic effect after a lapse of few seconds and due to this blood-pressure of ventral aorta may be increased as in the case of eel.

The effect of supraoptimal concentrations of sodium, potassium and calcium on the hearts are in accordance with other published reports on v,ertebrate hearts (WILSON 1972 and HATTING 1974). Except C a + + ions which cause a decreased rate whereas Na+ and K+ ions behave similarly but after a n initial increase.

An increase in temperature causes a marked increase in cardiac output, due almost entirely to an increase in heart rate. T,emperature presumably acts directly on the

256 Mishra et al .

pace-maker cells of the heart altering m,embrane permeability and increasing the intrinsic rate of these cells (RANDALL 1968). I n the present work we have conducted an experiment of the effects of hot and cold Ringers solution on heart-beat. H o t Ringers (38' C) about 6' C more than the environmental increased both the force of contraction and rate which corresponds with the findings of RANDALL (1968). Cold ringers (5'C) decreases the force of contraction and rates, thus it produced a negative chronotropic effect on A. cuchia's heart.

Summary

The effects of the following hormones - adrenaline, acetylcholine, atropine, oxy- tocin, reserpine (serpacil) and various ions were studied. I t was observ,ed that adrenaline increased the force and rate of contraction of the heart while acetyl- choline and reserpine (serpacil) depressed the same. With oxytocin initially there is decrease in the force of contraction which is then followed by its increase. High sodium and potassium ion concentrations stimulate the heart contraction slightly followed by a decrease in the force of contraction while calcium ion prevents contraction of the heart. Hot ringer solution increases the force of contraction of the heart while cold ringer produces opposite effect.

Zusammenfassung

Die Einwirkung einiger Hormone und Kationen auf die Intensitst und Kontraktions- geschwindigkeit des Herzens beim Sul3wasserschlammaaI Amphipnous cuchia (Ham.)

Die Einwirkung folgender Hormone, Adrenalin, Acetylcholin, Atropin, Oxytocin, Reserpin (Serpacil) und verschiedener Kationen auf die Intcnsitat und Kontraktions- geschwindigkeit des Herzens beim SiiRwasserschlammaaI, Amphipnous cuchia (Ham.), wurde in diesen Untersuchungen getestet.

Wahrend Adrenalin die Starke und Kontraktionsrate des Herzens vergroRert, tritt nach Behandlung mit Ac,etylcholin und Reserpin der gegenteilige Effekt auf. Nach Behandlung mit Oxytocin tritt zunachst eine Verminderung der Kontraktionsinten- sitat auf, gefolgt von einer verstarkten Herzkontraktion. Natrium- und Kaliumionen regen die Herzkontraktion leicht an. Dieser Phase folgt eine Herabsetzung der Herz- kontraktion durch eine verstarkte Einwirkung von Calciumionen, die die Kontrak- tionen hcrabsetzcn. Warme Ringerlosung intensiviert die Herzkontraktion, kalte Ringerlosung zeigt einen unigekehrten Effekt.

Acknowledgements

Authors wish to thank Dr . R. BRESSLER, University of Arizona Medical Centre for critical review of the manuscript. Th,ey are also indebted to Dr. K. 1'. SINGH and Dr. B. S. SRIVASTAVA, Medical College and Dr . P. K. PANDEY, Post-Graduate Department of Zoology, Bhagalpur University for their valuable advices and suggestions. The technical assistance of SRI BINOY KUMAR SINGH is highly appreciated.

A comparative study wi th pigs, poultry and ratj

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Central Institute fo r Nutrition and Food Research T N O , Zeist, T h e Netherlands Spelderholt Institute f o r Poultry Research, Beekbergen, T h e Netherlands

Institute for Animal Feeding and Nutrition Research "Hoorn'', Lelystad, T h e Netherlands

A comparative study with pigs, poultry and rats of the amino acid digestibility of diets containing crude protein with diverging

digestibilities'

By P. SLUMP and L. VAN BEEK, W. M. M. A. JANSSEN and K. TERPSTRA, N. P. LENIS and B. SMITS

Receipt of Ms. 11. 9. 1977

1. Introduction

Although several approaches have been made to determine the utilization of the individual amino acids in feed proteins, there is until now not a generally accepted standard method. The values used can be subdivided in:

' Financial support for this study was provided by thc Commodity Board for Stockfeeds, The l l ague

2. Ticrphysiol., Ticrernahrg. U. Futrermittelkde. 39 (1977), 257-272 @. 1977/78 Vcrlaj: Paul Parey, Hamburg und Berlin I5SN 0044-3565 ZTTSAA