Cardiac function and circulation in hagfishes

1991 ◽  
Vol 69 (7) ◽  
pp. 1985-1992 ◽  
Author(s):  
Malcolm E. Forster ◽  
Michael Axelsson ◽  
Anthony P. Farrell ◽  
Stefan Nilsson
Keyword(s):  
Cardiac Output ◽  
Cardiac Function ◽  
Energy Requirement ◽  
High Volume ◽  
Aortic Pressure ◽  
Arterial Blood ◽  
Branchial Heart ◽  
Blood Pressures

The hagfish circulation contains a high volume of blood (180 mL∙kg−1) and is remarkable for the number of accessory pumps. Cardiac output from the branchial heart of hagfishes is comparable to that of elasmobranch and most teleost fishes, but blood pressures are considerably lower than in any other vertebrate group. Cardiac output is extremely sensitive to both venous return and ventral aortic pressure (afterload). Owing to the low arterial blood pressures, myocardial power output is lower than for any other vertebrate heart. The concomitant low energy requirement of the myocardium allows ATP generated anaerobically through glycolysis to maintain cardiac output during severe hypoxia. In vivo and in vitro administration of adrenergic agonists and antagonists increase and decrease cardiac performance, respectively. This suggests that the catecholamines that are stored beneath the endothelium of the branchial and portal hearts are involved in the tonic control of cardiac function.

Influence of acute microwave radiation on cardiac function in normal and myocardial ischemic cats

1981 ◽  
Vol 50 (5) ◽  
pp. 931-935 ◽  
Author(s):  
M. J. Galvin ◽  
D. I. McRee
Keyword(s):  
Coronary Artery ◽  
Myocardial Ischemia ◽  
Microwave Irradiation ◽  
Cardiac Function ◽  
Microwave Radiation ◽  
Cardiac Tissue ◽  
Continuous Wave ◽  
Arterial Blood

Exposure of biological specimens to microwave radiation in vivo and in vitro has been reported to cause alterations to the cardiovascular system. In addition, microwave radiation may cause effects in damaged cardiac tissue that are not observed in normal tissue. In this study, we examined the influence of direct microwave irradiation (2.45 GHz, continuous wave) of the intact exposed heart on cardiac function in cats with and without myocardial ischemia. Myocardial ischemia was induced by occlusion of the left anterior descending coronary artery. In the sham-nonexposed and sham-plus-microwave exposed animals the coronary artery was isolated but not occluded. The exposed hearts were either irradiated at a specific absorption rate (SAR) of 30 mW/g or not irradiated, and were monitored for 5 h. At a SAR of 30 mW/g, the temperature of the exposed tissue increased at an initial rate of 0.43 degrees C/min in dead cats. However, in live animals, no increases in aortic blood temperatures occurred during irradiation. Mean arterial blood pressure, cardiac output, heart rate, plasma and myocardial creatine phosphokinase, and S-T segment were not influenced by 5 h of microwave irradiation of the myocardium in cats with or without myocardial ischemia.

In vitro myocardial performance after lethal and nonlethal doses of endotoxin

1986 ◽  
Vol 250 (2) ◽  
pp. H240-H246 ◽  
Author(s):  
K. H. McDonough ◽  
B. A. Brumfield ◽  
C. H. Lang
Keyword(s):  
Cardiac Output ◽  
Systolic Pressure ◽  
Myocardial Performance ◽  
Arterial Blood ◽  
Pressure Development ◽  
Heart Preparation ◽  
Higher Doses ◽  
Working Heart

The present study was initiated to determine whether the myocardial effects of an in vivo injection of endotoxin into rats were correlated with the dose and thus the lethality of the endotoxin administered. All animals in this study were used 4 h after a bolus injection of 1,000, 100, 10, or 1 microgram/100 g body wt of Escherichia coli endotoxin. At this time, mean arterial blood pressure had returned to control levels but cardiac output was still depressed at the three higher doses as previously reported [Am. J. Physiol. 248 (Regulatory Integrative Comp. Physiol. 17): R471-R478, 1985]. Intrinsic function of the myocardium was assessed using the isolated perfused working heart preparation. Cardiac output and pressure development were measured at varying preloads and at two levels of aortic outflow resistance. In vitro approaches were chosen for this study to eliminate peripheral vascular changes and humoral or neural alterations that might influence myocardial performance in vivo. Results indicate that coronary vascular resistance was increased in all hearts from endotoxin-treated animals compared with controls. In addition, myocardial performance was impaired at several doses of endotoxin, and the degree of dysfunction was dependent on the dose of endotoxin administered. Dysfunction, i.e., a depression in cardiac output times peak systolic pressure, was evident at the two higher doses in which there was 50 and 10% lethality by 24 h and also in the lower dose of 10 micrograms/100 g, which was nonlethal. Cardiac output appeared to be very sensitive to the consequences of endotoxin administration. Defects in myocardial performance could be revealed by increasing preload or afterload stress on the hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

Passage of labeled albumin into canine aortic wall in vivo and in vitro

1961 ◽  
Vol 200 (3) ◽  
pp. 622-624 ◽  
Author(s):  
Leroy E. Duncan ◽  
Katherin Buck
Keyword(s):  
Abdominal Aorta ◽  
Aortic Wall ◽  
Aortic Pressure ◽  
Ascending Aorta ◽  
Descending Aorta ◽  
Arterial Blood ◽  
Isolated Aorta ◽  
Abdominal Portion

The passage of labeled albumin into canine aortic wall in vivo and in vitro was studied. In vivo albumin entered the inner layer fastest in the ascending aorta and progressively less rapidly down the length of the aorta. In vitro, this gradient was partially preserved since albumin entered the inner layer of ascending aorta faster than that of descending aorta. The gradient was not completely preserved in vitro, since albumin entered the inner layer of abdominal aorta faster than that of descending thoracic aorta. The rapid entrance of albumin into the abdominal portion of the aorta in vitro appears to have been due to the maintenance of arterial blood pressure in the unusually dense capillary network of the abdominal aorta. The partial preservation of the gradient in the isolated aorta excludes phasic variation of intra- or extra-aortic pressure as a cause of the gradient.

Cardiovascular Changes in the Lingcod (Ophiodon Elongatus) Following Adrenergic and Cholinergic Drug Infusions

1981 ◽  
Vol 91 (1) ◽  
pp. 293-305
Author(s):  
A. P. FARRELL
Keyword(s):  
Cardiac Output ◽  
Stroke Volume ◽  
Cardiac Function ◽  
Cholinergic Agonists ◽  
Ophiodon Elongatus ◽  
Arterial Blood ◽  
Flow Profiles ◽  
Blood Pressures ◽  
Ventral Aorta ◽  
Cholinergic Drug

Adrenergic and cholinergic agonists were infused into the ventral aorta to evoke gill vasoactivity in the lingcod, Ophiodon elongatus. Arterial blood pressures were changed, and cardiac output and stroke volume were increased. As a consequence both the pressure and flow profiles across the gill were altered, and these changes should alter the pattern of lamellar perfusion. The changes in cardiac function were apparently reflexly mediated.

Cardiovascular Effects of Micromeria graeca (L.) Benth. ex Rchb in Normotensive and Hypertensive Rats

2020 ◽  
Vol 20 (8) ◽  
pp. 1253-1261
Author(s):  
Mourad Akdad ◽  
Mohamed Eddouks
Keyword(s):  
Blood Pressure ◽  
Cardiovascular System ◽  
Arterial Blood Pressure ◽  
Antihypertensive Activity ◽  
Computer Assisted ◽  
Hypertensive Rats ◽  
Vasorelaxant Effect ◽  
Arterial Blood

Aims: The present study was performed in order to analyze the antihypertensive activity of Micromeria graeca (L.) Benth. ex Rchb. Background: Micromeria graeca (L.) Benth. ex Rchb is an aromatic and medicinal plant belonging to the Lamiaceae family. This herb is used to treat various pathologies such as cardiovascular disorders. Meanwhile, its pharmacological effects on the cardiovascular system have not been studied. Objective: The present study aimed to evaluate the effect of aqueous extract of aerial parts of Micromeria graeca (AEMG) on the cardiovascular system in normotensive and hypertensive rats. Methods: In this study, the cardiovascular effect of AEMG was evaluated using in vivo and in vitro investigations. In order to assess the acute effect of AEMG on the cardiovascular system, anesthetized L-NAME-hypertensive and normotensive rats received AEMG (100 mg/kg) orally and arterial blood pressure parameters were monitored during six hours. In the sub-chronic study, rats were orally treated for one week, followed by blood pressure assessment during one week of treatment. Blood pressure was measured using a tail-cuff and a computer-assisted monitoring device. In the second experiment, isolated rat aortic ring pre-contracted with Epinephrine (EP) or KCl was used to assess the vasorelaxant effect of AEMG. Results: Oral administration of AEMG (100 mg/kg) provoked a decrease of arterial blood pressure parameters in hypertensive rats. In addition, AEMG induced a vasorelaxant effect in thoracic aortic rings pre-contracted with EP (10 μM) or KCl (80 mM). This effect was attenuated in the presence of propranolol and methylene blue. While in the presence of glibenclamide, L-NAME, nifedipine or Indomethacin, the vasorelaxant effect was not affected. Conclusion: This study showed that Micromeria graeca possesses a potent antihypertensive effect and relaxes the vascular smooth muscle through β-adrenergic and cGMP pathways.

Vasorelaxant and Antihypertensive Effects of Mentha pulegium L. in Rats: An in vitro and in vivo Approach

2020 ◽  
Vol 20 ◽  
Author(s):  
Mohammed Ajebli ◽  
Mohamed Eddouks
Keyword(s):  
Blood Pressure ◽  
Acute Experiment ◽  
Antihypertensive Activity ◽  
Mentha Pulegium ◽  
In Vitro Experiment ◽  
Arterial Blood ◽  
Dose Dependent ◽  
Ca2 Channels

Aims and objective: The aim of the study was to investigate the effect of aqueous aerial part extract of Mentha pulegium L. (Pennyrile) (MPAE) on arterial pressure parameters in rats. Background: Mentha pulegium is a medicinal plant used to treat hypertension in Morocco. Material and methods: In the current study, MPAE was prepared and its antihypertensive activity was pharmacologically investigated. L-NAME-hypertensive and normotensive rats have received orally MPAE (180 and 300 mg/kg) during six hours for the acute experiment and during seven days for the sub-chronic treatment. Thereafter, systolic, diastolic, mean arterial blood pressure and heart rate were evaluated. While, in the in vitro experiment, isolated denuded and intact thoracic aortic rings were suspended in a tissue bath system and the tension changes were recorded. Results: A fall in blood pressure was observed in L-NAME-induced hypertensive treated with MPAE. The extract also produced a dose-dependent relaxation of aorta pre-contracted with NE and KCl. The study showed that the vasorelaxant ability of MPAE seems to be exerted through the blockage of extracellular Ca2+ entry. Conclusion: The results demonstrate that the extract of pennyrile exhibits antihypertensive activity. In addition, the effect may be, at least in part, due to dilation of blood vessels via blockage of Ca2+ channels.

Abstract 14391: Transient Cell Cycle Induction in Cardiomyocytes is a Promising Approach to Treat Ischemia Induced Heart Failure

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Riham Abouleisa ◽  
Qinghui Ou ◽  
Xian-liang Tang ◽  
Mitesh Solanki ◽  
Yiru Guo ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cardiac Function ◽  
Single Cell ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Cardiomyocyte Proliferation ◽  
Specific Expression ◽  
Control Virus

Rationale: The regenerative capacity of the heart to repair itself after myocardial infarction (MI)is limited. Our previous study showed that ectopic introduction of Cdk1/CyclinB1 andCdk4/CyclinD1 complexes (4F) promotes cardiomyocyte proliferation in vitro and in vivo andimproves cardiac function after MI. However, its clinical application is limited due to the concernsfor tumorigenic potential in other organs. Objectives: To first, identify on a single cell transcriptomic basis the necessary reprogrammingsteps that cardiomyocytes need to undertake to progress through the proliferation processfollowing 4F overexpression, and then, to determine the pre-clinical efficacy of transient andcardiomyocyte specific expression of 4F in improving cardiac function after MI in small and largeanimals. Methods and Results: Temporal bulk and single cell RNAseq of mature hiPS-CMs treated with4F or LacZ control for 24, 48, or 72 h revealed full cell cycle reprogramming in 15% of thecardiomyocyte population which was associated with sarcomere disassembly and metabolicreprogramming. Transient overexpression of 4F specifically in cardiomyocytes was achievedusing non-integrating lentivirus (NIL) driven by TNNT2 (TNNT2-4F-NIL). One week after inductionof ischemia-reperfusion injury in rats or pigs, TNNT2-4F-NIL or control virus was injectedintramyocardially. Compared with controls, rats or pigs treated with TNNT2-4F-NIL showed a 20-30% significant improvement in ejection fraction and scar size four weeks after treatment, asassessed by echocardiography and histological analysis. Quantification of cardiomyocyteproliferation in pigs using a novel cytokinesis reporter showed that ~10% of the cardiomyocyteswithin the injection site were labelled as daughter cells following injection with TNNT2-4F-NILcompared with ~0.5% background labelling in control groups. Conclusions: We provide the first understanding of the process of forced cardiomyocyteproliferation and advanced the clinical applicability of this approach through minimization ofoncogenic potential of the cell cycle factors using a novel transient and cardiomyocyte-specificviral construct.

Nervous control of the heartbeat in octopus

1980 ◽  
Vol 85 (1) ◽  
pp. 111-128 ◽  
Author(s):  
M. J. Wells
Keyword(s):  
Circulatory System ◽  
Aortic Pressure ◽  
Surgical Removal ◽  
Cardiac Ganglion ◽  
Nervous Control ◽  
Cardiac Ganglia ◽  
Before And After ◽  
Branchial Heart ◽  
Systemic Heart

The circulatory system of cephalopods is based on a trio of hearts, with two pairs of associated ganglia linked to the CNS by a pair of visceral nerves. The beat of the hearts was recorded from free-moving octopuses before and after surgical removal or disconnexion of elements of the nervous system. Severing the visceral nerves does not stop the hearts, which continue to beat in a powerful well co-ordinated manner in isolation from the CNS. The nerves seem to be concerned in raising the cardiac output in exercise, and with stopping the hearts when mantle movements cease, but they are not necessary for the initiation of maintenance of the normal rhythm. Removal of the fusiform ganglia severs all nervous connexions between the ywo gill hearts, and deprives the systemic heart of its nerve supply. The trio of hearts continues to beat as strongly as before. Removal or disconnexion of a cardiac ganglion disrupts the beat of the corresponding gill heart which now tends to contract in an ill-coordinated and rather feeble manner, though at much the same frequency as before; with both cardiacs gone the systemic heart, which contracts only when it is filled, tends to drop in frequency and the mean aortic pressure falls. The system remains rhythmic, however, and the beat may recover, to the point where aortic pressures and frequencies approach those found in intact animals at rest; even octopuses with both fusiform and both cardiac ganglia removed can survive for many hours. From the performance of the isolated branchial heart, the existence of a pulsating vesicle in each cardiac ganglion, the effects of cardiac ganglion removal and the remarkable steadiness of heartbeat frequency shown by intact animals under a variety of conditions, it is argued that the heartbeat rhythm is normally controlled by pacemakers in the branchial heart/ cardiac ganglion complexes, and perhaps, in intact animals, from within the cardiac ganglia themselves. The picture of the control of the heartbeat that emerges from the study of free moving essentially intact animals is quite different from that arising from in vitro and acute preparation studies. It suggests that the conventional wisdom about the control of the heartbeat in cephalopods (and perhaps by implication, in other molluscs) may need to be considerably revised.

Effects of natriuretic peptides and nitroprusside on venous function in trout

1997 ◽  
Vol 273 (2) ◽  
pp. R527-R539 ◽  
Author(s):  
K. R. Olson ◽  
D. J. Conklin ◽  
A. P. Farrell ◽  
J. E. Keen ◽  
Y. Takei ◽  
...  
Keyword(s):  
Natriuretic Peptide ◽  
Natriuretic Peptides ◽  
Aortic Pressure ◽  
Systemic Resistance ◽  
Venous Compliance ◽  
Venous Capacitance ◽  
Unstressed Volume ◽  
Ventral Aorta

Active venous regulation of cardiovascular function is well known in mammals but has not been demonstrated in fish. In the present studies, the natriuretic peptides (NP) rat atrial natriuretic peptide (ANP) and trout ventricular natriuretic peptide (VNP), clearance receptor inhibitor SC-46542, and sodium nitroprusside (SNP) were infused into unanesthetized trout fitted with pressure cannulas in the ventral aorta, dorsal aorta, and ductus Cuvier, and a ventral aorta (VA) flow probe was used to measure cardiac output (CO). In another group, in vivo vascular (venous) capacitance curves were obtained during ANP or SNP infusion. The in vitro effects of NP on vessels and the heart were also examined. ANP, VNP, and SC-46542 decreased central venous pressure (PVen), CO, stroke volume (SV), and gill resistance (RG), whereas systemic resistance (RS) and heart rate (HR) increased. Dorsal aortic pressure (PDA) transiently increased and then fell even though RS remained elevated. ANP decreased mean circulatory filling pressure (MCFP), increased vascular compliance at all blood volumes, and increased unstressed volume in hypovolemic fish. ANP had no direct effect on the heart. ANP responses in vivo were not altered in trout made hypotensive by prior treatment with the angiotensin-converting enzyme inhibitor lisinopril. SNP reduced ventral aortic pressure (PVA), PDA, and RS, increased CO and HR, but did not affect PVen, SV, or RG. SNP slightly decreased MCFP but did not affect compliance or unstressed volume. In vitro, large systemic arteries were more responsive than veins to NP, whereas SNP relaxed both. These results show that, in vivo, NP decrease venous compliance, thereby decreasing venous return, CO, and arterial pressure. Conversely, SNP hypotension is due to decreased RS. This is the first evidence for active regulation of venous capacitance in fish, which probably occurs in small veins or venules. The presence of venous baroreceptors is also suggested.

Sign in / Sign up

Export Citation Format

Share Document