The importance of nervous and humoral mechanisms in the control of cardiac performance in the Atlantic cod Gadus morhua at rest and during non-exhaustive exercise

1988 ◽  
Vol 137 (1) ◽  
pp. 287-301 ◽  
Author(s):  
M. Axelsson
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Gadus Morhua ◽  
Positive Inotropic Effect ◽  
Atlantic Cod ◽  
Inotropic Effect ◽  
Response Curves

The nervous regulation of heart rate and stroke volume in the Atlantic cod Gadus morhua was investigated both in vivo, during rest and exercise, and in vitro. The cholinergic and adrenergic influences on the heart were estimated in experiments with injections of atropine and sotalol. At rest the cholinergic and adrenergic tonus on the heart were 38% and 21%, respectively (ratio 1.81:1). At the end of an exercise period, the cholinergic tonus had decreased to 15% but the adrenergic tonus had increased to 28% (ratio 0.54:1). The results suggest that variation of the cholinergic tonus on the heart is a major factor in the regulation of the heart rate. In one group of fish, cardiac output was also measured, allowing calculation of stroke volume. Cardiac output increased significantly during exercise, and this effect persisted in the presence of both atropine and sotalol, although the increase in heart rate was reduced or abolished. The persisting increase in cardiac output during exercise is due to an increase in stroke volume, reflecting a Starling relationship. In the presence of the adrenergic neurone-blocking agent bretylium, a positive inotropic effect on isolated, paced atrial and ventricular strips was observed. In the atrial preparations the effect persisted after 24 h. The effect was prevented by pretreatment with sotalol or cocaine, but potentiated by phentolamine pretreatment. This shows that bretylium exerts its neurone-blocking action after being taken up into the adrenergic nerves, and suggests that the positive inotropic effect of bretylium observed in vivo is due to release of endogenous catecholamines. The concentration-response curves for adrenaline on isolated spontaneously beating atrial preparations showed that the concentrations of catecholamines necessary to produce appreciable effects on the heart are higher than the concentrations found in cod plasma during ‘stress’ situations (handling and exhaustive swimming).

Increased ventricular stiffness and decreased cardiac function in Atlantic cod (Gadus morhua) at high temperatures

2013 ◽  
Vol 305 (8) ◽  
pp. R864-R876 ◽  
Author(s):  
Douglas A. Syme ◽  
A. Kurt Gamperl ◽  
Gordon W. Nash ◽  
Kenneth J. Rodnick
Keyword(s):  
Stroke Volume ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Isometric Force ◽  
Full Range ◽  
Large Strains ◽  
High Heart Rate ◽  
Ventricular Filling ◽  
Ventricular Trabeculae

We employed the work loop method to study the ability of ventricular and atrial trabeculae from Atlantic cod to sustain power production during repeated contractions at acclimation temperatures (10°C) and when acutely warmed (20°C). Oxygen tension (Po2) was lowered from 450 to 34% air saturation to augment the thermal stress. Preparations worked under conditions simulating either a large stroke volume (35 contractions/min rate, 8–12% muscle strain) or a high heart rate (70 contractions/min, 2–4% strain), with power initially equal under both conditions. The effect of declining Po2 on power was similar under both conditions but was temperature and tissue dependent. In ventricular trabeculae at 10°C (and atria at 20°C), shortening power declined across the full range of Po2 studied, whereas the power required to lengthen the muscle was unaffected. Conversely, in ventricular trabeculae at 20°C, there was no decline in shortening power but an increase in lengthening power when Po2 fell below 100% air saturation. Finally, when ventricular trabeculae were paced at rates of up to 115 contractions/min at 20°C (vs. the maximum of 70 contractions/min in vivo), they showed marked increases in both shortening and lengthening power. Our results suggest that although elevated heart rates may not impair ventricular power as they commonly do isometric force, limited atrial power and the increased work required to expand the ventricle during diastole may compromise ventricular filling and hence, stroke volume in Atlantic cod at warm temperatures. Neither large strains nor high contraction rates convey an apparent advantage in circumventing this.

A study of the physiological consequences of sympathetic denervation of the heart caused by the arterial switch procedure

2010 ◽  
Vol 20 (2) ◽  
pp. 150-158 ◽  
Author(s):  
Cecilia Falkenberg ◽  
Stefan Hallhagen ◽  
Krister Nilsson ◽  
Boris Nilsson ◽  
Ingegerd Östman-Smith
Keyword(s):  
Heart Rate ◽  
Coronary Flow ◽  
Arterial Switch Operation ◽  
Sympathetic Nerves ◽  
Heart Weight ◽  
Maximal Heart Rate ◽  
Response Curves ◽  
Arterial Switch

AbstractBackgroundThe arterial switch operation is the corrective operation for transposition of the great arteries, defined as the combination of concordant atrioventricular and discordant ventriculo–arterial connections, but there have been concerns about silent subendocardial ischaemia on exercise and coronary artery growth. The arterial switch divides the majority of the sympathetic nerves entering the heart; we have studied the effects of coronary flow and sensitivity to catecholamine stimulation in an animal model.MethodsA total of 10 piglets were operated on cardiopulmonary bypass with section and resuturing of aortic trunk, pulmonary artery and both coronary arteries, with 13 sham-operated controls. After 5–7 weeks of recovery, seven simulated switch survivors and 13 controls were studied.ResultsBasal heart rate was significantly higher in switch piglets: in vivo mean (standard deviation) 112 (12) versus sham 100 (10) beats per minute, (p = 0.042); in vitro (Langendorff preparation): 89 (9) versus sham 73 (8) beats per minute (p = 0.0056). In vivo maximal heart rate in response to epinephrine was increased in switch piglets, 209 (13) versus 190 (17) beats per minute (p = 0.044). In vitro dose–response curves to norepinephrine were shifted leftward and upwards (p = 0.0014), with an 80% increase in heart rate induced by 0.095 (0.053) norepinephrine micromole per litre perfusate in switch hearts versus 0.180 (0.035) norepinephrine micromole per litre (p = 0.023). Increase in coronary flow on norepinephrine stimulation and maximal coronary flow were significantly reduced in switch hearts: 0.3 (0.2) versus 0.8 (0.4) millilitre per gram heart weight (p = 0.045) and 2.5 (0.4) versus 3.1 (0.4) millilitre per gram heart (p = 0.030), respectively.ConclusionsA combination of increased intrinsic heart rate, increased sensitivity to chronotropic actions of norepinephrine, and a decreased maximal coronary flow creates potential for a mismatch between perfusion and energy demands.

MECHANICAL PERFORMANCE OF AN IN SITU PERFUSED HEART FROM THE TURTLE CHRYSEMYS SCRIPTA DURING NORMOXIA AND ANOXIA AT 5 C AND 15 C

1994 ◽  
Vol 191 (1) ◽  
pp. 207-229 ◽  
Author(s):  
A Farrell ◽  
C Franklin ◽  
P Arthur ◽  
H Thorarensen ◽  
K Cousins
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Power Output ◽  
Mechanical Performance ◽  
Perfused Heart ◽  
Inotropic Effects ◽  
Ventricular Mass

We developed an in situ perfused turtle (Chrysemys scripta) heart preparation to study its intrinsic mechanical properties at 5°C and 15°C using normoxic and anoxic perfusion conditions. The in situ preparation proved durable and stable. At 15°C and a spontaneous heart rate of 23.4 beats min-1, maximum stroke volume was 2.54 ml kg-1 body mass, maximum cardiac output was 62.5 ml min-1 kg-1 and maximum cardiac myocardial power output was 1.50 mW g-1 ventricular mass. There was good agreement between these values and those previously obtained in vivo. Furthermore, since the maximum stroke volume observed here was numerically equivalent to that observed in ventilating C. scripta in vivo, it seems likely that C. scripta has little scope to increase stroke volume to a level much beyond that observed in the resting animal through intrinsic mechanisms alone. The ability of the perfused turtle heart to maintain stroke volume when diastolic afterload was raised (homeometric regulation) was relatively poor. At 5°C, the spontaneous heart rate (8.1 beats min-1) was threefold lower and homeometric regulation was impaired, but maximum stroke volume (2.25 ml kg-1) was not significantly reduced compared with the value at 15°C. The significantly lower maximum values for cardiac output (18.9 ml min-1 kg-1) and power output (0.39 mW g-1 ventricular mass) at 5°C were largely related to pronounced negative chronotropy with only a relatively small negative inotropy. Anoxia had weak negative chronotropic effects and marked negative inotropic effects at both temperatures. Negative inotropy affected pressure development to a greater degree than maximum flow and this difference was more pronounced at 5°C than at 15°C. The maximum anoxic cardiac power output value at 15°C (0.77 mW g-1 ventricular mass) was not that different from values previously obtained for the performance of anoxic rainbow trout and hagfish hearts. In view of this, we conclude that the ability of turtles to overwinter under anoxic conditions depends more on their ability to reduce cardiac work to a level that can be supported through glycolysis than on their cardiac glycolytic potential being exceptional.

Novel in vivo and in vitro mechanisms of positive inotropic effect of atractylodin

2020 ◽  
Author(s):  
Li Gao ◽  
Yuwei Wang ◽  
Wenhui Zhang ◽  
Xiaojia Zhu ◽  
Qianwen Gao ◽  
...  
Keyword(s):  
Positive Inotropic Effect ◽  
Inotropic Effect

scholarly journals Kinetics of Calcium Fluxes Across the Intestinal Mucosa of the Marine Teleost, Gadus Morhua, Measured Using an In Vitro Perfusion Method

1988 ◽  
Vol 140 (1) ◽  
pp. 171-186 ◽  
Author(s):  
KRISTINA SUNDELL ◽  
BJÖRN THRANDUR BJÖRNSSON
Keyword(s):  
Intestinal Mucosa ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Calcium Influx ◽  
Calcium Excretion ◽  
Passive Component ◽  
Marine Teleost ◽  
Atpase Inhibitor

An in vitro technique for perfusion of the intestinal vasculature and lumen was developed and used to measure calcium (Ca2+) fluxes across the intestinal mucosa of the marine teleost, the Atlantic cod (Gadus morhua). Saturable and nonsaturable components of the calcium influx and efflux were determined. The calcium influx had one passive component and one saturable component, following Michaelis-Menten kinetics with Km = 8.41mmoll−1 and Vmax = 0.604μmol Ca2+ kg−1 h−1. At physiological Ca2+ concentrations in the vascular ([Ca2+] = l.9mmoll−1) and luminal ([Ca2+] =14.9mmoll−1) perfusion fluids, the saturable component amounted to 60% of the Ca2+ influx. The high-affinity Ca2+-ATPase inhibitor chlorpromazine (CP, 10−4moll−1) antagonized 45% of the Ca2+ influx. The Ca2+ efflux across the intestinal mucosa of the cod was a saturable process, following Michaelis-Menten kinetics with Km =6.15mmoll−1 and Vmax =3.79μmol Ca2+ kg−1h−1, but insensitive to CP (l0−5moll−1). The Ca2+ efflux was l.22μumol Ca2+ kg−1 h−1, representing about 20% of the total calcium excretion and about 50% of the extrarenal excretion of the Atlantic cod in vivo.

scholarly journals Involvement of β3-Adrenoceptor in Altered β-Adrenergic Response in Senescent Heart

2008 ◽  
Vol 109 (6) ◽  
pp. 1045-1053 ◽  
Author(s):  
Aurélie Birenbaum ◽  
Angela Tesse ◽  
Xavier Loyer ◽  
Pierre Michelet ◽  
Ramaroson Andriantsitohaina ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Electron Paramagnetic Resonance ◽  
Positive Inotropic Effect ◽  
Inotropic Effect ◽  
Paramagnetic Resonance ◽  
Beta Adrenergic ◽  
Adrenergic Response ◽  
Electron Paramagnetic

Background In senescent heart, beta-adrenergic response is altered in parallel with beta1- and beta2-adrenoceptor down-regulation. A negative inotropic effect of beta3-adrenoceptor could be involved. In this study, the authors tested the hypothesis that beta3-adrenoceptor plays a role in beta-adrenergic dysfunction in senescent heart. Methods beta-Adrenergic responses were investigated in vivo (echocardiography-dobutamine, electron paramagnetic resonance) and in vitro (isolated left ventricular papillary muscle, electron paramagnetic resonance) in young adult (3-month-old) and senescent (24-month-old) rats. Nitric oxide synthase (NOS) immunolabeling (confocal microscopy), nitric oxide production (electron paramagnetic resonance) and beta-adrenoceptor Western blots were performed in vitro. Data are mean percentages of baseline +/- SD. Results An impaired positive inotropic effect (isoproterenol) was confirmed in senescent hearts in vivo (117 +/- 23 vs. 162 +/- 16%; P < 0.05) and in vitro (127 +/- 10 vs. 179 +/- 15%; P < 0.05). In the young adult group, the positive inotropic effect was not significantly modified by the nonselective NOS inhibitor N-nitro-L-arginine methylester (L-NAME; 183 +/- 19%), the selective NOS1 inhibitor vinyl-L-N-5(1-imino-3-butenyl)-L-ornithine (L-VNIO; 172 +/- 13%), or the selective NOS2 inhibitor 1400W (183 +/- 19%). In the senescent group, in parallel with beta3-adrenoceptor up-regulation and increased nitric oxide production, the positive inotropic effect was partially restored by L-NAME (151 +/- 8%; P < 0.05) and L-VNIO (149 +/- 7%; P < 0.05) but not by 1400W (132 +/- 11%; not significant). The positive inotropic effect induced by dibutyryl-cyclic adenosine monophosphate was decreased in the senescent group with the specific beta3-adrenoceptor agonist BRL 37344 (167 +/- 10 vs. 142 +/- 10%; P < 0.05). NOS1 and NOS2 were significantly up-regulated in the senescent rat. Conclusions In senescent cardiomyopathy, beta3-adrenoceptor overexpression plays an important role in the altered beta-adrenergic response via induction of NOS1-nitric oxide.

scholarly journals Nervous control of the blood pressure in the Atlantic cod, Gadus morhua

1985 ◽  
Vol 117 (1) ◽  
pp. 335-347 ◽  
Author(s):  
D. G. Smith ◽  
S. Nilsson ◽  
I. Wahlqvist ◽  
B. M. Eriksson
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Blocking Agent ◽  
Adrenergic Innervation ◽  
Nervous Control ◽  
Aortic Blood ◽  
Aortic Blood Pressure

Dorsal (PDA) and ventral aortic blood pressure (PVA) and heart rate (HR) were measured in conscious resting cod, Gadus morhua L., which has been allowed 24 h recovery from surgery. Plasma adrenalin and nonadrenalin concentrations in these fish were 3.4 and 2.2 nmoll-1 respectively, and thus lower than previously reported values from partially recovered cod. Twenty-four hours after treatment with the adrenergic neurone blocking agent bretylium, PDA was significantly reduced by 17% compared to sham-injected controls, although PVA and heart rate were unaltered. Subsequent alpha-adrenoceptor blockade by phentolamine produced no further fall in PDA and no changes in PVA or HR, provided a 5-h period was allowed to overcome the acute toxic side effects of phentolamine. The effectiveness of the bretylium or phentolamine blockade was confirmed by noting the absence of any vasoconstrictor response during sympathetic nerve stimulation in perfused tails from fish used in the in vivo experiments. Bretylium had no significant effect on the sensitivity of the isolated coeliac artery to adrenalin, but effectively blocked the adrenergic innervation of this artery or the vasculature of the tail. Evidence for a non-selective blockade of non-adrenergic nerves to the heart was also obtained. It is concluded that the adrenergic tonus affecting the dorsal aortic blood pressure in resting cod that have recovered for 24 h following surgery is due solely to an adrenergic nervous tone.

Overexpression of Cyclic Adenosine Monophosphate Effluent Protein MRP4 Induces an Altered Response to β-Adrenergic Stimulation in the Senescent Rat Heart

2015 ◽  
Vol 122 (2) ◽  
pp. 334-342 ◽  
Author(s):  
Aude Carillion ◽  
Sarah Feldman ◽  
Cheng Jiang ◽  
Fabrice Atassi ◽  
Na Na ◽  
...  
Keyword(s):  
Positive Inotropic Effect ◽  
Cyclic Adenosine Monophosphate ◽  
Calcium Transient ◽  
Adenosine Monophosphate ◽  
Left Ventricular ◽  
Inotropic Effect ◽  
Inotropic Response ◽  
Adrenergic Stimulation

Abstract Background: In the senescent heart, the positive inotropic response to β-adrenoceptor stimulation is reduced, partly by dysregulation of β1- and β3-adrenoceptors. The multidrug resistance protein 4 (MRP4) takes part in the control of intracellular cyclic adenosine monophosphate concentration by controlling its efflux but the role of MRP4 in the β-adrenergic dysfunction of the senescent heart remains unknown. Methods: The β-adrenergic responses to isoproterenol were investigated in vivo (stress echocardiography) and in vitro (isolated cardiomyocyte by Ionoptix® with sarcomere shortening and calcium transient) in young (3 months old) and senescent (24 months old) rats pretreated or not with MK571, a specific MRP4 inhibitor. MRP4 was quantified in left ventricular homogenates by Western blotting. Data are mean ± SD expressed as percent of baseline value. Results: The positive inotropic effect of isoproterenol was reduced in senescent rats in vivo (left ventricular shortening fraction 120 ± 16% vs. 158 ± 20%, P < 0.001, n = 16 rats) and in vitro (sarcomere shortening 129 ± 37% vs. 148 ± 35%, P = 0.004, n = 41 or 43 cells) as compared to young rats. MRP4 expression increased 3.6-fold in senescent compared to young rat myocardium (P = 0.012, n = 8 rats per group). In senescent rats, inhibition of MRP4 by MK571 restored the positive inotropic effect of isoproterenol in vivo (143 ± 11%, n = 8 rats). In vitro in senescent cardiomyocytes pretreated with MK571, both sarcomere shortening (161 ± 45% vs. 129 ± 37%, P = 0.007, n = 41 cells per group) and calcium transient amplitude (132 ± 25% vs. 113 ± 27%, P = 0.007) increased significantly. Conclusion: MRP4 overexpression contributes to the reduction of the positive inotropic response to β-adrenoceptor stimulation in the senescent heart.

Early Stages in the Recovery to Injury in the Dorsal Fin of the Atlantic Cod (Gadus morhua)

1964 ◽  
Vol 21 (2) ◽  
pp. 347-354
Author(s):  
P. M. Townsley ◽  
M. L. Hughes
Keyword(s):  
Gadus Morhua ◽  
Wound Closure ◽  
Atlantic Cod ◽  
Epidermal Cells ◽  
Dorsal Fin ◽  
Early Stages ◽  
Close Proximity ◽  
Cell Mitosis

The early stages in the recovery of the dorsal fin of the Atlantic cod (Gadus morhua) to a "clean cut injury" are described. It is concluded that the observed rapid epidermal migration, wound closure and cell mitosis are essentially the same in in-vivo as in in-vitro experiments. An accumulation of carbohydrate material occurs in the outermost layer of epidermal cells. There is a change in the carbohydrate composition or structure in the dermal layers at the site of injury. The basal epidermal cells rapidly divide in the in-vitro culture whereas only those basal epidermal cells in an in-vivo injury in close proximity to the injury divide. The surrounding nutrient medium in in-vitro cultures does not appear to be involved in the initial cell migration. However, ascorbic acid does stimulate epidermal migration, mucous secretion, and basal epidermal cell mitosis.

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