scholarly journals Depressed cardiac contractility and its postnatal development in rats after chemical sympathectomy

2008 ◽  
pp. 507-515
Author(s):  
J Švíglerová ◽  
J Kuncová ◽  
L Nalos ◽  
J Slavíková ◽  
M Štengl

The contribution of the sympathetic innervation to the postnatal development of cardiac contractility remains unclear. In this study, the postnatal maturation of cardiac contractility was compared in control rats and rats after chemical sympathectomy. The chemical sympathectomy was induced by administration of 6-hydroxydopamine to newborn rats. At days 20, 40 and 60 of postnatal life, the contractile parameters and concentrations of sympathetic neurotransmitters were measured in both right and left ventricles. In rats with chemical sympathectomy, concentrations of norepinephrine were reduced almost completely in both ventricles at all time points. The contractility of the left ventricle papillary muscles was substantially decreased at all time points. In contrast, the contractility of the right ventricle papillary muscles was decreased only transiently, showing a recovery at day 60 regardless of the permanently decreased concentration of norepinephrine. The concentration of neuropeptide Y, another neurotransmitter present in sympathetic nerves, showed the same developmental trend as contractility: permanent reduction in the left ventricle, transient reduction with a recovery at day 60 in the right ventricle. The data indicate that the sympathetic nervous system plays an important role in the postnatal development of cardiac contractility and neuropeptide Y may contribute to this effect.

2018 ◽  
Vol 24 (2) ◽  
pp. 77-81
Author(s):  
Tobă Marius ◽  
Iliescu Dan Marcel ◽  
Bordei Petru ◽  
Popescu-Chiriloaie Cristina ◽  
Gheorghiţescu Jancă Ruxandra

Abstract We used formalinized heart dissection obtained from forensic laboratory in Constanta, analyzing the papillary muscles and their tendon chordae. We studied at the papillary muscles the number of forms that could be in single or multiple muscular bodies, encountering more than five body muscles in a papillary muscle group. We measured using caliper graduated in millimeters, the height of each papillary muscle body (from the base to its upper end) and its thickness at the base and at its upper extremity. Chordae tendon we examined in terms of their origin and number at the level of each papillary muscle, the dimensions (length and thickness), orientation and how they end at the atrioventricular valves. We noted the presence of „false”chordae tendineae, which were disposed between the papillary muscle and the ventricular wall. The results were compared with data in the literature that I had the opportunity to consult


2014 ◽  
Vol 31 (04) ◽  
pp. 225-227
Author(s):  
R. Miguel ◽  
R. Reinaldo ◽  
K. Fraga ◽  
A. Galvão ◽  
J. Silva ◽  
...  

Abstract Introduction: Caracara plancus, popularly known as Carcará, is a bird with broad geographic distribution, occurring from the southern United States to Argentina. Owing to importance of the heart during the flight and the lack of studies of this body in caracaras, this research aimed to conduct the description of the morphology and internal and external morphology heart Caracara plancus. Materials and Methods: Using a magnifying glass (TECNIVAL, SQF-F), precision scale and steel caliper, the heart three caracaras were described morphologically, weighed and measured. Results: The weight of hearts averaged 7,246g ± 0,518g. The mean side-to-side axis was 2,196cm ± 0,085cm and 3,366cm ± 0,036cm the longitudinal axis. In the side wall of the right ventricle was obtained the value of 0,185cm ± 0,035cm in the lateral wall of the left ventricle 0,59cm ± 0,014cm and interventricular septum 0,014cm ± 0.52cm. The heart of Carcará has no anterior interventricular groove; however there is the presence of the posterior interventricular sulcus. Internally, the left ventricle was observed, the presence of atrioventricular valves formed by connective tissue 18 tendinous cords, papillary muscles and a bridge crests. In the right ventricle, the atrioventricular valve was formed by muscle tissue and did not submit chordae, papillary muscles, crests or bridge. Conclusion: The heart of Carcará features in its morphology similar to the hearts of other birds and can be checked one right atrioventricular valve constituted by muscle tissue.


1995 ◽  
Vol 7 (3) ◽  
pp. 451 ◽  
Author(s):  
JJ Smolich

The heart undergoes marked ultrastructural alterations during fetal and postnatal development. Early in fetal development, cardiac myocytes contain abundant pools of glycogen, scattered mitochondria and sparse, peripheral myofibrils. Transverse tubules are absent, and sarcoplasmic reticulum and intercalated discs are poorly developed. During late fetal and early postnatal development, myofibrils extend into the myocyte interior and attain a mature appearance, and the glycogen pools are reduced in size. In addition, transverse tubules develop and the morphological appearance of the sarcoplasmic reticulum and intercalated disc becomes increasingly complex. Experimental studies in sheep, corroborated by clinical studies in humans, also point to marked functional changes during development. In the fetus, the right ventricle is the dominant pumping chamber because right ventricular output exceeds left ventricular output, while pulmonary arterial and aortic pressures are similar. This functional difference is reflected in myocardial blood flow patterns, with blood flow to the right ventricle exceeding that to the left ventricle. The ventricular outputs equalize after birth, but a functional left ventricular dominance rapidly emerges following a postnatal increase in systemic vascular resistance and a decrease in pulmonary vascular resistance. This postnatal switchover in functional dominance is accompanied by a corresponding alteration in the relative level of ventricular myocardial blood flows. Consistent with right ventricular dominance in utero, myocytes in the right ventricle of the fetal sheep are larger and contain more myofibrillar material than those in the left ventricle. Left ventricular myocytes become larger than right ventricular myocytes after birth, but this adaptation to altered postnatal haemodynamics requires some weeks to become fully established.


1991 ◽  
Vol 261 (6) ◽  
pp. H1979-H1987 ◽  
Author(s):  
M. Gopalakrishnan ◽  
D. J. Triggle ◽  
A. Rutledge ◽  
Y. W. Kwon ◽  
J. A. Bauer ◽  
...  

To examine the status of ATP-sensitive K+ (K+ATP) channels and 1,4-dihydropyridine-sensitive Ca2+ (Ca2+DHP) channels during experimental cardiac failure, we have measured the radioligand binding properties of [3H]glyburide and [3H]PN 200 110, respectively, in tissue homogenates from the rat cardiac left ventricle, right ventricle, and brain 4 wk after myocardial infarction induced by left coronary artery ligation. The maximal values (Bmax) for [3H]glyburide and [3H]PN 200 110 binding were reduced by 39 and 40%, respectively, in the left ventricle, and these reductions showed a good correlation with the right ventricle-to-body weight ratio in heart-failure rats. The ligand binding affinities were not altered. In the hypertrophied right ventricle, Bmax values for both the ligands were not significantly different when data were normalized to DNA content or right ventricle weights but showed an apparent reduction when normalized to unit protein or tissue weight. Moderate reductions in channel densities were observed also in whole brain homogenates from heart failure rats. Assessment of muscarinic receptors, beta-adrenoceptors and alpha 1-adrenoceptors by [3H]quinuclidinyl benzilate, [3H]dihydroalprenolol, and [3H]prazosin showed reductions in left ventricular muscarinic and beta-adrenoceptor densities but not in alpha 1-adrenoceptor densities, consistent with earlier observations. It is suggested that these changes may in part contribute to the pathology of cardiac failure.


1987 ◽  
Vol 253 (6) ◽  
pp. H1381-H1390 ◽  
Author(s):  
W. L. Maughan ◽  
K. Sunagawa ◽  
K. Sagawa

To analyze the interaction between the right and left ventricle, we developed a model that consists of three functional elastic compartments (left ventricular free wall, septal, and right ventricular free wall compartments). Using 10 isolated blood-perfused canine hearts, we determined the end-systolic volume elastance of each of these three compartments. The functional septum was by far stiffer for either direction [47.2 +/- 7.2 (SE) mmHg/ml when pushed from left ventricle and 44.6 +/- 6.8 when pushed from right ventricle] than ventricular free walls [6.8 +/- 0.9 mmHg/ml for left ventricle and 2.9 +/- 0.2 for right ventricle]. The model prediction that right-to-left ventricular interaction (GRL) would be about twice as large as left-to-right interaction (GLR) was tested by direct measurement of changes in isovolumic peak pressure in one ventricle while the systolic pressure of the contralateral ventricle was varied. GRL thus measured was about twice GLR (0.146 +/- 0.003 vs. 0.08 +/- 0.001). In a separate protocol the end-systolic pressure-volume relationship (ESPVR) of each ventricle was measured while the contralateral ventricle was alternatively empty and while systolic pressure was maintained at a fixed value. The cross-talk gain was derived by dividing the amount of upward shift of the ESPVR by the systolic pressure difference in the other ventricle. Again GRL measured about twice GLR (0.126 +/- 0.002 vs. 0.065 +/- 0.008). There was no statistical difference between the gains determined by each of the three methods (predicted from the compartment elastances, measured directly, or calculated from shifts in the ESPVR). We conclude that systolic cross-talk gain was twice as large from right to left as from left to right and that the three-compartment volume elastance model is a powerful concept in interpreting ventricular cross talk.


2019 ◽  
Vol 11 (1) ◽  
pp. 123-126
Author(s):  
Sruti Rao ◽  
Robert D. Stewart ◽  
Gosta Pettersson ◽  
Carmela Tan ◽  
Suzanne Golz ◽  
...  

Enlargement of the bulboventricular foramen (BVF) in double-inlet left ventricle or the ventricular septal defect (VSD) in tricuspid atresia with transposition of the great arteries is one approach for prevention or treatment of systemic ventricular outflow obstruction. Most often, BVF/VSD restriction is bypassed preemptively or addressed directly at the time of Glenn/Fontan procedures as part of staged univentricular palliation. We describe a patient who underwent enlargement of a restrictive VSD during Fontan completion and subsequently presented with an asymptomatic pseudoaneurysm of the right ventricle at the ventriculotomy site.


1956 ◽  
Vol 187 (1) ◽  
pp. 135-138 ◽  
Author(s):  
Martin M. Winbury

Papillary muscles from the right ventricle of the cat were subjected to periods of anoxia ranging from 15–60 minutes with and without glucose in the Krebs-Henseleit (bicarbonate) solution. Under aerobic conditions glucose was not required in the medium for the maintenance of contraction strength. Under anaerobic conditions the contraction strength decreased rapidly and after 30 minutes of oxygen deficiency contractile activity ceased. Reintroduction of oxygen after 15 minutes of anoxia resulted in full recovery of contraction strength for both control and glucose deficient muscles. After longer periods of anoxia, aerobic recovery was greater for muscles with glucose present during the anaerobic period. Little aerobic recovery was noted for muscles in glucose deficient medium during the 60 minutes of anoxia.


1976 ◽  
Vol 231 (3) ◽  
pp. 781-785 ◽  
Author(s):  
OM Brown

The distribution of acetylcholine (ACh) in the cat heart was investigated by a pyrolysis-gas chromatography (PGC) method. The hearts were dissected into various regions and homogenized in acetonitrile in the presence of propionylcholine, internal standard. Following extraction with toluene and hexane, the choline esters were precipitated as the enneaiodide complex. The isolated choline esters were analyzed by PGC, and the peak corresponding to ACh was quantified. The compound extracted from heart tissue that eluted with the retention time of authentic ACh was identified by mass spectrometry as dimethylaminoethylacetate, the pyrolysis product of ACh. ACh concentrations were found to be higher in the atria than the ventricles. In both the atria and the ventricles, a higher content of ACh was found in the right than the left portions: right ventricle, 5.0 compared to left ventricle, 2.0 nmol/g; and right atrium, 16.8 compared to left atrium, 11.3 nmol/g. Some cats were subjected to a bilateral cervical vagotomy 3 wk before removal and analysis of heart tissue. Hearts from vagotomized cats contained less ACh than controls in the right ventricle (-31%), right atrium (-54%), SA node (-42%), and papillary muscle (-53%), but no decreases were found in the left ventricle, left atrium, or interventricular septum.


2008 ◽  
Vol 53 (No. 3) ◽  
pp. 165-168 ◽  
Author(s):  
W. Perez ◽  
M. Lima ◽  
G. Pedrana ◽  
F. Cirillo

In the present study the most outstanding anatomical findings of the heart of a giraffe are described. Two papillary muscles were found in the right ventricle, namely magnus and subarterial. There were no papillary parvi muscles. The supraventricular crest gave insertion to various tendinous chords. These chords fixed the angular cusp of the right atrioventricular valve. The pectinate muscles were better developed in the left auricle than in the right one. Within the left ventricle two big papillary muscles were found as well as a notorious septomarginal trabecula. The left coronary artery irrigated the majority of the heart’s territory. It gave origin to the interventricular paraconal branch and to the circumflex branch. The latter gave off the branch of the left ventricular border and the interventricular subsinosal branch.


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