scholarly journals The effect of stimulation of left atrial receptors on coronary blood flow in anaesthetized dogs.

1989 ◽  
Vol 408 (1) ◽  
pp. 45-56 ◽  
Author(s):  
M J Drinkhill ◽  
D Kaye ◽  
D A Mary
Keyword(s):  
Blood Flow ◽  
Coronary Blood Flow ◽  
Left Atrial ◽  
Atrial Receptors ◽  
Stimulation Of

Influence of carotid sinus pressure on atrial receptors and renal blood flow

1982 ◽  
Vol 242 (2) ◽  
pp. H220-H226
Author(s):  
F. Karim ◽  
D. U. Mackay ◽  
C. T. Kappagoda
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Left Atrial ◽  
Renal Mass ◽  
Carotid Sinus ◽  
Systemic Arterial Pressure ◽  
Left Pulmonary Vein ◽  
Atrial Receptors ◽  
Sinus Pressure ◽  
Stimulation Of

Stimulation of the atrial receptors results in an increase in renal blood flow. The present investigation was undertaken to determine whether this response was modulated by the input from the baroceptors in the carotid sinus. The experiments were performed on dogs anesthetized with chloralose. The systemic arterial pressure was held constant. The carotid sinuses were perfused at 62 +/- 1.3, 95 +/- 2.7, and 145 +/- 8.3 mmHg. The atrial receptors were stimulated by distension of small balloons positioned at the left pulmonary vein-atrial junctions and the left atrial appendage. At a carotid sinus pressure of 62 +/- 1.3 mmHg, the blood flow increased from 182 +/- 8.5 to 199 +/- 8.9 ml . min-1 . 100 g-1 renal mass. At a carotid sinus pressure of 95 +/- 2.7 mmHg, the blood flow increased from 202 +/- 9.6 to 209 +/- 10.4 ml . min-1 . 100 g-1 renal mass. At a carotid sinus pressure of 145 +/- 8.3 mmHg, the blood flow increased from 237 +/- 13.0 to 239 +/- 12.5 ml . min-1 . 100 g-1 renal mass. The first two responses alone were statistically significant. The response at a carotid sinus pressure of 62 +/- 1.3 mmHg was abolished by cutting or cooling the cervical vagi to 8--10 degrees C. It is concluded that stimulation of the left atrial receptors produces a reflex increase in blood flow to the kidney, and this response is modulated by the input from the carotid sinus baroceptors.

THROMBOLYSIS BY TISSUE-PLASMNOCEN ACTIVATOR AND A FIBRIN (OCEN) -DEGRADATION PRODUCT, PEPTIDE 6A, IN A CANINE MDDEL OF ELECTRICALLY-INDUCED CORONARY THROMBOSIS

1987 ◽  
Author(s):  
T Saldeen ◽  
J Mehta ◽  
W Nichols ◽  
D Lew
Keyword(s):  
Blood Flow ◽  
Coronary Blood Flow ◽  
Coronary Thrombosis ◽  
Canine Model ◽  
Peak Effect ◽  
Endothelial Surface ◽  
Tissue Plasminogen ◽  
Flow Restoration ◽  
Mean Time ◽  
Stimulation Of

Intracoronary thrombus resulting in acute myocardial ischemia can be lysed by thrombolytic agents, such as, streptokinase or t-PA. We examined the potential of a recombitant tissue-plasminogen activator (rt-PA)and a fibrin (ogen)-degradation productpentapeptide 6A, Ala-Arg-Pro-Ala-Lys, corresponding to aminoacids 43-47 in the BB-chain of fibrinogen, which causes marked increase in coronary blood flow and stimulates prostacyclin release, in restoring coronary blood flow in dqgs with experimentally-induced thrombus. An occlusive thrombus was created in the circumflex (Cx) coronary artery in 8 dcgs by electricalstimulation of the endothelial surface. The electrically-induced Cx thrombus consisted primarily of platelets and fibrin. After the occlusive thrcmbus was stable without electrical currant, rt-PA (10ug/kg/minute for 30 minutes intravenously)or peptide 6A (5 unoles/minute for 20 minutes intracorcnary) were randomly administered. Infusion of t-PA restored coronar blood flow (peak 22 ±12 ml/minute, mean ±SD) in five of seven animlas. The time to flow restoration was 12.3 ± 9.1 minutes and the reflow persistedfor20.0 ± 10.9 minutes. Peptide 6A administration also restored coronary blood flow (peak 20 ± 4 ml/ minute) in seven of eight animals with occlusive coronary thrombus. Mean time to blood flow restoration (4.3 ±2.9 minutes) wasshorter(P>0.05) than with rt-PA, but thereflow persisted only for the duration of tine infusion (16.3 ± 10.2 minutes).Peptide 6A adninistration was associatedwith a significant (P±0.05) increase in plasma 6-keto-PGF1α indicating stimulation of prostacyclin release. In addition, plasma t-PA concentrations also increased (F>0.01) at the peak effect of peptide 6A indicating releaseof endogenous t-PA as another potentialmechanism of the thrombolytic effects of peptide 6A. This study demonstrates that peptide 6A exerts coronary thrombolytic effectsccmpa rable to those of t-PA in a canine model of coronary thrombosis.

"Summation" of the increase in heart rate from stimulation of atrial receptors

1980 ◽  
Vol 58 (6) ◽  
pp. 666-672
Author(s):  
P. V. Greenwood ◽  
C. T. Kappagoda
Keyword(s):  
Heart Rate ◽  
Left Atrial ◽  
Superior Vena ◽  
Right Atrial ◽  
Propranolol Hydrochloride ◽  
Superior Vena Caval ◽  
The Right ◽  
Atrial Receptors ◽  
Stimulation Of ◽  
Wire Cage

In dogs anaesthetized with chloralose, application of stimuli which are likely to activate left atrial (L.A.) and right atrial (R.A.) receptors (complex unencapsulated endings) has been shown to result in an increase in heart rate. The present investigation was undertaken to determine whether the response elicited by the application of one stimulus (i.e., to the left atrium) could be enhanced by the application of a second stimulus (i.e., to the right atrium) in the same animal.The L.A. receptors were stimulated by distending a small balloon at the right upper pulmonary vein-L.A. junction and the R.A. receptors by "expanding" a spherical wire cage positioned at the superior vena caval (S.V.C.)-R.A. junction. Pressures in the S.V.C., R.A., L.A., and femoral artery were measured and the electrocardiogram monitored.In eight dogs stimulation of L.A. receptors resulted in an increase in heart rate (H.R.) of 18.5 beats/min (SEM 6.0; N = 23). In the same animals stimulation of R.A. receptors resulted in an increase in H.R. of 14.6 beats/min (SEM 2.0; N = 25). Application of both stimuli simultaneously resulted in an increase of 32.2 beats/min (SEM 8.0; N = 13). In four dogs propranolol hydrochloride (0.5 mg/kg) markedly diminished the response. In three dogs the response was abolished by bretylium tosylate (10 mg/kg).It is concluded that the increase in H.R. resulting from the application of these two stimuli could be "summated" and these findings support the proposition that the receptors in the two atria act as a functional entity.

Chronotropic, inotropic, and coronary artery blood flow responses to stimulation of specific canine sympathetic nerves and ganglia

1984 ◽  
Vol 62 (11) ◽  
pp. 1374-1381 ◽  
Author(s):  
R. D. Janes ◽  
D. E. Johnstone ◽  
J. A. Armour
Keyword(s):  
Blood Flow ◽  
Electrical Stimulation ◽  
Coronary Blood Flow ◽  
Stellate Ganglion ◽  
Sympathetic Nerves ◽  
Neural Stimulation ◽  
Intramyocardial Pressure ◽  
Intact Heart ◽  
Cardiac Nerves ◽  
Stimulation Of

Electrical stimulation of the major sympathetic cardiac nerves and ganglia in chloralose-anesthetized, open-chest dogs elicited specific changes in heart rate, coronary blood flow, regional intramyocardial pressure, or intraventricular pressure. The effects produced by stimulation of a cardiac nerve were similar to, but never greater than those produced by stimulation of the ipsilateral stellate ganglion. Coronary blood flow was increased when neural stimulation increased intramyocardial pressure. In contrast, coronary blood flow was not altered significantly when neural stimulation induced tachycardia without increasing intramyocardial pressure. It is concluded that in the intact heart, electrical stimulation of the sympathetic cardiac nerves or ganglia increases coronary blood flow by augmenting intramyocardial pressure, not chronotropism.

scholarly journals Mechanisms Involving Myocardial Injury in Tropical Stings and Bites

2017 ◽  
Vol 2017 ◽  
pp. 1-3
Author(s):  
Thirunavukarasu Kumanan ◽  
Mahesan Guruparan ◽  
Ratnasamy Vithiya ◽  
Indika Gawarammana
Keyword(s):  
Blood Flow ◽  
Coronary Blood Flow ◽  
Myocardial Injury ◽  
Coronary Vasospasm ◽  
Toxic Substances ◽  
Rare Entity ◽  
Acute Myocardial Injury ◽  
Russell’S Viper ◽  
Stimulation Of

It is known that a number of toxic substances produce myocardial injury by several mechanisms involving interruption of coronary blood flow due to stimulation of clotting mechanism and coronary vasospasm. Number of toxic substances may cause direct myocardial toxicity independent of coronary blood flow. Acute myocardial injury due to stings and bites is a rare entity and not well understood. Here we illustrate a case of myocardial injury due to Russell’s viper envenomation.

scholarly journals DIURESIS FROM STIMULATION OF LEFT ATRIAL RECEPTORS: INITIAL PURIFICATION STEPS FROM PLASMA OF THE CAUSATIVE AGENT

1981 ◽  
Vol 66 (4) ◽  
pp. 439-445
Author(s):  
Meryl F. Knapp ◽  
R. J. Linden ◽  
M. Joan Pearson ◽  
J. M. Pither ◽  
Elaine M. Whitaker
Keyword(s):  
Causative Agent ◽  
Left Atrial ◽  
Atrial Receptors ◽  
Stimulation Of

Importance of injection site for coronary blood flow determinations by microspheres in rats

1982 ◽  
Vol 242 (1) ◽  
pp. H94-H97 ◽  
Author(s):  
P. Wicker ◽  
R. C. Tarazi
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Injection Site ◽  
Coronary Blood Flow ◽  
Left Atrial ◽  
Left Ventricular ◽  
Significant Difference ◽  
Standard Deviations

Because coronary blood flow (CBF) determinations require that blood and microspheres be uniformly mixed in the root of the aorta, we developed a technique of left-atrial (LA) catheterization in rats and compared the variability of results obtained by LA injection and left-ventricular (LV) injection as regards systemic [cardiac output (CO)], proximal (coronary), and distal (renal, cerebral) flows in anesthetized animals. CBF values averaged 410 +/- 224 and 358 +/- 99 (SD) ml.min-1.100 g-1 from LV and LA injection, respectively, or 5.7 +/- 2.9 and 4.9 +/- 1.3 (SD) %CO. The variability with LA injection was significantly lower than with LV injection as shown by the marked differences in standard deviations obtained with the two methods (224 vs. 99 ml.min-1.100 g-1 or 2.9 vs. 1.3 %CO, P greater than 0.01). In contrast, no significant difference in variability was found for either CO or more distal regional flows. These results indicate that LV injections might be adequate for systemic flow and regional flows to relatively distal beds but that accurate measurements of CBF require LA injection of microspheres.

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