Right atrial stretch decreases supraoptic neurosecretory activity and plasma vasopressin

1981 ◽  
Vol 241 (1) ◽  
pp. R44-R49
Author(s):  
R. P. Menninger
Keyword(s):  
Left Atrial ◽  
Supraoptic Nucleus ◽  
Right Atrial ◽  
Vasopressin Release ◽  
Plasma Vasopressin ◽  
Neurosecretory Neurons ◽  
Plasma Arginine ◽  
Right Atrial Appendage ◽  
The Right ◽  
Atrial Receptors

It is generally held that left atrial stretch (LAS) but not right atrial stretch (RAS) reflexly inhibits vasopressin release and results in a diuresis. To reexamine the influence of RAS on the release of vasopressin and on the behavior of antidromically identified supraoptic neurosecretory neurons, RAS and LAS were applied in pentobarbital-anesthetized cats. Weighted 20 or 30 g sutures were placed in the left atrium pulmonary vein junction and at the base of the right atrial appendage. Antidromically identified supraoptic nucleus neurons were inhibited by both RAS and LAS applied independently and together, although fewer neurons were responsive to RAS alone. Simultaneous stretch of both atria resulted in greater inhibition of these neurons than did stretch of either atrium alone. Stretch of the right atrium alone also resulted in a significant decrease in plasma arginine vasopressin measured by radioimmunoassay. Differences between these results and other reports may stem from differences in the method of RAS or the specific right atrial receptors affected.

Effects of carotid occlusion and left atrial stretch on supraoptic neurosecretory cells

1979 ◽  
Vol 237 (1) ◽  
pp. R63-R67 ◽  
Author(s):  
R. P. Menninger
Keyword(s):  
Carotid Artery ◽  
Left Atrial ◽  
Supraoptic Nucleus ◽  
Neuronal Response ◽  
Plasma Osmolality ◽  
Neurosecretory Cells ◽  
Carotid Occlusion ◽  
Plasma Vasopressin ◽  
Neurosecretory Neurons ◽  
The Right

Acute experiments were performed on pentobarbital-anesthetized cats to determine whether atrial and carotid baroreceptors affected the same neurosecretory neurons in the supraoptic nucleus (SON) of the hypothalamus. The osmosensitivity of these neurons was also determined. Eighty-two SON neurons were antidromically identified and 63 of these increased their firing rates during complete occlusion of the right carotid artery. Further testing of these 63 neurons demonstrated that 56 were inhibited by directly stretching the left atrium and 61 were excited by intracarotid injection of hypertonic saline. Left atrial stretch greatly reduced the neuronal response to carotid occlusion. These results show that the activity of the majority of the antidromically identified SON neurons is altered by left atrial and carotid artery receptors as well as changes in plasma osmolality. Results are consistent with the known influence of these receptors on plasma vasopressin.

Distension of the pulmonary vein – atrial junctions and plasma vasopressin in the chloralose-anaesthetized dog

1983 ◽  
Vol 61 (8) ◽  
pp. 905-910 ◽  
Author(s):  
N. Wilson ◽  
J. R. Ledsome
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Pulmonary Vein ◽  
Arginine Vasopressin ◽  
Left Atrial ◽  
Vagus Nerves ◽  
Plasma Vasopressin ◽  
Plasma Arginine ◽  
Atrial Receptors ◽  
Anaesthetized Dog

The effects of localized distension of the pulmonary vein–left atrial junctions on plasma arginine vasopressin (AVP) have been examined in chloralose anaesthetized dogs. Pulmonary vein distension caused an increase in heart rate and a decrease in plasma AVP concentration. Cooling the vagosympathetic nerves to 10 °C caused an increase in arterial pressure and plasma AVP concentration and prevented the changes in heart rate and plasma AVP concentration caused by pulmonary vein distension. Cooling the vagus nerves to 16 °C did not change heart rate, arterial pressure, or plasma AVP concentration but significantly reduced the changes in heart rate and plasma AVP concentration caused by pulmonary vein distension. Propranolol (0.5 mg/kg) decreased heart rate and prevented the increase in heart rate associated with pulmonary vein distension but did not abolish the decrease in plasma AVP concentration. It is concluded that distension of the pulmonary vein – left atrial junctions causes a decrease in plasma AVP concentration by stimulating atrial receptors with myelinated afferent fibres. The decrease in plasma AVP concentration is not secondary to the reflex changes in heart rate caused by pulmonary vein distension.

"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.

Effect of stimulating right atrial receptors on renal blood flow

1982 ◽  
Vol 60 (12) ◽  
pp. 1672-1679 ◽  
Author(s):  
F. Karim ◽  
S. Kaufman ◽  
C. T. Kappagoda
Keyword(s):  
Blood Flow ◽  
Renal Mass ◽  
Carotid Sinus ◽  
Superior Vena ◽  
Renal Perfusion ◽  
Right Atrial ◽  
Myelinated Fibres ◽  
Right Atrial Appendage ◽  
The Right ◽  
Atrial Receptors

This investigation was undertaken to determine the effect of stretching the superior vena caval – right atrial (SVC–RA) junction and the right atrial appendage on blood flow to the kidney (RBF) and to establish whether any changes observed were influenced by the input from the baroreceptors in the carotid sinus. The experiments were performed on seven dogs, anaesthetized with α-chloralose. The systemic arterial (i.e., renal perfusion) pressure was held constant. At a carotid sinus pressure (CSP) of 59.0 ± 1.2 mmHg (1 mmHg = 133.322 Pa), the RBF increased from 218 ± 16.1 to 231.7 ± 18.4 mL/min per 100 g renal mass (p < 0.025). At a CSP of 88.0 ± 3.5 mmHg, the RBF increased from 230.1 ± 19.2 to 237.1 ± 19.2 mL/min per 100 g renal mass (p < 0.05). At a CSP of 137 ± 3.7 mmHg there were no significant changes in RBF. These responses were abolished by cutting (four dogs) or cooling the vagi (one dog only). In a subsidiary investigation it was shown that stretching the SVC–RA junction activated receptors in the endocardial surface of the right atrium which discharged into myelinated fibres in the vagi, having an average conduction velocity of 8.1 m/s (range 3.8–15). It is concluded that stimulation of right atrial receptors increases the RBF and that this response is influenced by the input from the barorceptors in the carotid sinus.

Role of atrial receptors in the control of ACTH

1976 ◽  
Vol 231 (3) ◽  
pp. 692-699 ◽  
Author(s):  
AJ Baertschi ◽  
DG Ward ◽  
DS Gann
Keyword(s):  
Quantitative Analysis ◽  
Left Atrium ◽  
Left Atrial ◽  
Right Atrial ◽  
Plasma Acth ◽  
Volume Changes ◽  
Firing Rates ◽  
The Right ◽  
Atrial Receptors

Sinusoidal volume changes (+/- 1 ml) were applied at 1 Hz to the right or left atrium of 25 anesthetized cats. Changes in firing rates of single vagal fibers and in plasma ACTH and cortisol were observed in response to start and stop of atrial pulsation. Decreased activity of right atrial and/or septal B-receptors was associated with increased ACTH. Changes in left atrial B-receptor activity were associated with a change in ACTH only if right atrial/septal receptors or baroreceptors also changed their activity in the same direction. The activity of atrial A-receptors did not change in response to atrial pulsation. A quantitative analysis suggested strongly that right atrial and/or septal B-receptors dominate in the response of ACTH to hemodynamic stimuli. Arterial receptors appear less effective, and left atrial B-receptors appear least effective in the hemodynamic control of ACTH.

The Apical View Sign for Easier Identification of Left Juxtaposition of the Right Atrial Appendage

2020 ◽  
Vol 11 (5) ◽  
pp. 641-642
Author(s):  
Nitin Madan ◽  
Anitha Parthiban ◽  
Richard Lorber
Keyword(s):  
Left Atrial ◽  
Left Atrial Appendage ◽  
Atrial Appendage ◽  
Right Atrial ◽  
Cardiac Malformation ◽  
Congenital Cardiac Malformation ◽  
Apical View ◽  
Right Atrial Appendage ◽  
The Right ◽  
Coronal View

Left juxtaposition of the right atrial appendage (RAA) is a rare congenital cardiac malformation, where both atrial appendages are located leftward of the great arteries. Despite well-described echocardiographic markers, this diagnosis remains challenging to establish, especially for the novice imager. We describe the apical view sign in three patients with juxtaposed RAA. We noted that the normal left atrial appendage was visualized from the apical four-chamber or equivalent coronal view at the level of the atrioventricular valves.

Cobra head deformity of atrial septal occluder: blessing in disguise

2020 ◽  
pp. 1-2
Author(s):  
Uma Devi Karuru ◽  
Saurabh Kumar Gupta
Keyword(s):  
Atrial Septal Defect ◽  
Left Atrial ◽  
Septal Defect ◽  
Atrial Septum ◽  
Right Atrial ◽  
Septal Occluder Device ◽  
Occluder Device ◽  
The Right

Abstract It is not uncommon to have prolapse of the atrial septal occluder device despite accurate measurement of atrial septal defect and an appropriately chosen device. This is particularly a problem in cases with large atrial septal defect with absent aortic rim. Various techniques have been described for successful implantation of atrial septal occluder in such a scenario. The essence of all these techniques is to prevent prolapse of the left atrial disc through the defect while the right atrial disc is being deployed. In this brief report, we illustrate the use of cobra head deformity of the device to successfully deploy the device across the atrial septum.

Control of atrial natriuretic factor by right and left atrial distension in pregnant sheep

1995 ◽  
Vol 268 (6) ◽  
pp. R1411-R1417
Author(s):  
D. Javeshghani ◽  
S. Mukaddam-Daher ◽  
L. Fan ◽  
Z. Guan ◽  
J. Gutkowska ◽  
...  
Keyword(s):  
Atrial Natriuretic Factor ◽  
Left Atrial ◽  
Atrial Pressure ◽  
Right Atrial ◽  
Natriuretic Factor ◽  
Pregnant Sheep ◽  
Vascular Catheters ◽  
The Right ◽  
Left Atrial Distension ◽  
Atrial Natriuretic

Previous studies of the atrial stretch-atrial natriuretic factor (ANF) relationship during pregnancy have employed volume expansion and measured only right atrial pressure (RAP). Consequently, we studied nonpregnant (n = 7) and 115- to 125-day pregnant (n = 7) sheep and assessed the ANF response to changes of RAP and left atrial pressure (LAP) induced by graded balloon inflation. Ewes prepared with vascular catheters and atrial balloons were studied after recovery from preparatory surgical procedures. The basal levels of mean arterial pressure (MAP, 83 +/- 3 mmHg), RAP (2.1 +/- 0.7 mmHg), LAP (4.7 +/- 0.9 mmHg), and heart rate (HR, 102 +/- 6 beats/min) were similar in nonpregnant and pregnant sheep. Pregnancy also resulted in elevation of ANF concentration from 25 +/- 6 to 57 +/- 4 fmol/ml. With right atrial distension, the RAP-ANF relationships were similar in both nonpregnant and pregnant sheep, with a 10-mmHg increase in RAP increasing ANF by an average of 95 +/- 9 fmol/ml. In nonpregnant sheep, the LAP-ANF relationship was more responsive than RAP-ANF because a 10-mmHg increase in LAP resulted in a 193 +/- 10 fmol/ml increase in ANF. Moreover, during pregnancy, the LAP-ANF relationship was significantly more sensitive because a 10-mmHg increase in LAP resulted in a 433 +/- 15 fmol/ml elevation of ANF. These data demonstrate that plasma ANF levels are more responsive to distension of the left atria than to the right. More importantly, the ANF response to left, but not right, atrial distension is enhanced by pregnancy.

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