Response of supraoptic neurosecretory cells to changes in left atrial distension

1979 ◽  
Vol 236 (5) ◽  
pp. R261-R267
Author(s):  
R. P. Menninger
Keyword(s):  
Left Atrium ◽  
Left Atrial ◽  
Supraoptic Nucleus ◽  
Neurosecretory Cells ◽  
Simultaneous Increase ◽  
Atrial Wall ◽  
Firing Rates ◽  
Series Of Experiments ◽  
Atrial Receptors ◽  
Left Atrial Distension

Acute studies were conducted in cats to determine the effects of small changes in left atrial pressure (LAP) on the activity of antidromically identified neurons in the supraoptic nucleus (SON). Inflation of left atrial balloons reproducibly altered the frequency of 15% of the SON neurons. More than half of these increased frequency, probably due to a simultaneous increase in arterial pressure. In a second series, the firing rates of 20% of the SON neurons tested were inversely related to changes in LAP produced by pumping blood into or out of the left atrium. A third series of experiments were conducted in which the left atrium was directly stretched by pulling on a suture placed in the atrial wall in addition to one of the above methods of changing LAP. Directly stretching the left atrium inhibited over 70% of the SON neurons; this included all the neurons that responded to changes in LAP. The results suggest that these SON neurons have differential sensitivities to inputs from left atrial receptors.

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.

scholarly journals Porcelain Atrium: A Case Report with Literature Review

2011 ◽  
Vol 2011 ◽  
pp. 1-3 ◽  
Author(s):  
Krystle Leacock ◽  
Andre J. Duerinckx ◽  
Bonnie Davis
Keyword(s):  
Left Atrium ◽  
Left Atrial ◽  
Radiographic Imaging ◽  
Atrial Wall ◽  
X Ray ◽  
Left Atrial Wall ◽  
Nigerian Woman ◽  
Wall Calcification ◽  
Noncontrast Ct ◽  
Chest X Ray

Massive left atrial wall calcification, or porcelain atrium, is very rare. We describe a case of an unusual pattern of cardiac calcification demonstrated on routine preoperative chest X-ray for cataract surgery in a 71-year-old Nigerian woman. Past medical history was significant for mitral stenosis and atrial fibrillation. Radiographic imaging revealed curvilinear high density areas of calcification outlining the left atrium on the chest X-ray. Noncontrast CT scan of the thorax confirmed the left atrial distribution of calcification and, thus, the diagnosis of porcelain left atrium.

Natriuresis during atrial distension and a concurrent decline in plasma atriopeptin

1988 ◽  
Vol 255 (2) ◽  
pp. R259-R267 ◽  
Author(s):  
K. L. Goetz ◽  
B. C. Wang ◽  
P. Bie ◽  
R. J. Leadley ◽  
P. G. Geer
Keyword(s):  
Sodium Excretion ◽  
Left Atrial ◽  
Volume Expansion ◽  
Dominant Role ◽  
Urine Flow ◽  
Time Period ◽  
Series Of Experiments ◽  
Composite Response ◽  
Circulating Levels ◽  
Left Atrial Distension

In the conscious dog, left atrial distension elicits a composite response that modulates both cardiovascular and renal function. The response to atrial distension may be mediated by the combined effects of neural reflexes and the release of atriopeptin. To assess the relative contributions of atrial reflex mechanisms and circulating atriopeptin to the renal response elicited by atrial distension, alpha-human atrial natriuretic peptide (alpha-hANP) was infused into conscious dogs at 50 ng.kg-1.min-1 for 60 min. Then the infusion was stopped abruptly, and left atrial pressure was increased 8 mmHg by inflating a balloon positioned above the mitral valve. Plasma atriopeptin decreased during the 40-min period of atrial distension, but urine flow and sodium excretion increased during this time. In another series of experiments, volume expansion was substituted for atrial distension. Saline (24 ml/kg) was infused intravenously for 5 min immediately after the 60-min period of alpha-hANP infusion. Urine flow and sodium excretion increased after administration of saline even though plasma atriopeptin decreased substantially during the same time period. These results provide evidence that circulating levels of atriopeptin do not play a dominant role in influencing sodium excretion either during atrial distension or in response to saline infusion.

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.

Paroxysmal Postprandial Atrial Fibrilation Suppressed by Laparoscopic Repair of a Giant Paraesophageal Hernia Compressing the Left Atrium

2015 ◽  
Vol 24 (1) ◽  
pp. 113-116 ◽  
Author(s):  
Daniel A. Cristian ◽  
Alin S. Constantin ◽  
Mariana Barbu ◽  
Dan Spătaru ◽  
Traean Burcoș ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrium ◽  
Laparoscopic Repair ◽  
Left Atrial ◽  
Paraesophageal Hernia ◽  
Surgical Repair ◽  
Atrial Wall ◽  
Left Atrial Wall ◽  
Atrial Fibrilation

We present the case of a patient with a giant paraesophageal hernia associated with paroxysmal postprandial atrial fibrillation that was suppressed after surgery. The imaging investigations showed the intrathoracic displacement of a large part of the stomach, which pushed the left atrial wall causing atrial fibrillation. The laparoscopic surgical repair acted as sole treatment for this condition.

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.

Electrophysiological differentiation of oxytocin-and vasopressin-secreting neurones

1977 ◽  
Vol 196 (1125) ◽  
pp. 367-384 ◽  
Keyword(s):  
High Frequency ◽  
Firing Pattern ◽  
Neurosecretory Cells ◽  
Vasopressin Release ◽  
Firing Rates ◽  
High Frequency Discharge ◽  
Continuous Type ◽  
Vasopressin Secretion ◽  
Series Of Experiments ◽  
Urethane Anaesthesia

Antidromically identified neurosecretory cells of the paraventricular (p. v.) and supraoptic (s. o.) nuclei of the hypothalamus were recorded in lactating rats under urethane anaesthesia during reflex milk ejection (m. e.) and haemorrhage. Eighty one p. v. and s. o. neurones were studied. Their background firing rates ranged from < 0.1 to 6.3 spikes/s and three distinct patterns of activity were encountered: slow irregular (73%), fast continuous (10%) and phasic (17%). Forty units (49%) displayed a brief (2-4 s) high-frequency discharge (30-60 spikes/s) correlated with suckling-induced m. e., and these were classified as m. e. (oxytocin-secreting) neurones. The remainder of the cells showed no activation at this time and were classified as non-m. e. neurones. Ten m. e. neurones tested through haemorrhage (5 ml of blood) showed a gradual acceleration of firing rates, reaching a maximum of 3.7 ± 0.7 spikes/s (mean + s. e.) about 20 min after blood withdrawal. The firing pattern of the m. e. neurones therefore changed from a slow irregular to a fast continuous type. By contrast, 11 non-m. e. neurones tested with the same procedure showed a rapid activation reaching a maximum of 6.4 ±0.6 spikes/s by the fourth minute. Non-m. e. neurones which were initially of the slow irregular type, first became fast continuous and later evolved into a highly characteristic phasic pattern of activity which was never induced in the m. e. neurones. After the blood was replaced, all the cells returned to their original firing pattern. In a parallel series of experiments, plasma samples taken 5 and 25 min after haemorrhage showed a ten-fold elevation in antidiuretic activity. A slight but non-significant increase in m. e. activity was also observed. Thus p. v. and s. o. neurosecretory cells may be electrophysically differentiated into two functionally distinct populations: (1) oxytocin releasing neurones which show a high-frequency discharge before m. e. induced by suckling, and (2) vasopressin-releasing neurones which adopt a phasic pattern of firing during vasopressin release induced by haemorrhage. We suggest that the rate of vasopressin secretion into the circulation largely depends on the proportion of vasopressin neurones firing phasically, their firing rates within the phases and the duration and degree of synchronization of the phases.

scholarly journals Diffuse Gallium-67 Accumulation in the Left Atrial Wall Detected Using SPECT/CT Fusion Images

2016 ◽  
Vol 2016 ◽  
pp. 1-3 ◽  
Author(s):  
Kohei Kotani ◽  
Joji Kawabe ◽  
Shigeaki Higashiyama ◽  
Atsushi Yoshida ◽  
Susumu Shiomi
Keyword(s):  
Computed Tomography ◽  
Atrial Fibrillation ◽  
Left Atrium ◽  
Left Atrial ◽  
Emission Computed Tomography ◽  
Atrial Wall ◽  
Left Atrial Wall ◽  
Abnormal Accumulation ◽  
Fusion Images ◽  
Gallium 67

Gallium-67 scintigraphy is useful for detecting active inflammation. We show a 66-year-old female patient with atrial fibrillation and diffuse thickening of the left atrial wall due to acute myocarditis, who presented diffuse abnormal accumulation of gallium-67 in the left atrium on single photon emission computed tomography/computed tomography (SPECT/CT) fusion images. In the second gallium-67 scan 2 months after the first scintigraphy, the abnormal accumulation in the heart was no longer visible. Gallium-67 SPECT/CT images helped understanding the disease condition that temporary inflammation in the left atrium caused atrial fibrillation.

Atrial receptors and renal function

1975 ◽  
Vol 55 (2) ◽  
pp. 157-205 ◽  
Author(s):  
K. L. Goetz ◽  
G. C. Bond ◽  
D. D. Bloxham
Keyword(s):  
Renal Function ◽  
Left Atrium ◽  
Left Atrial ◽  
Urine Flow ◽  
Atrial Pressure ◽  
Pulmonary Vasculature ◽  
Positive Pressure ◽  
Atrial Volume ◽  
Pulmonary Hemodynamics ◽  
Atrial Receptors

The hypothesis that receptors in the heart or pulmonary vasculature initiate a reflex that influences urine flow was derived from experiments designed to evaluate the effect of mechanical ventilation on renal function. These experiments indicated that urine flow usually decreases during positive-pressure breathing and usually increases during negative-pressure breathing. It was surmised that impulses from certain cardiopulmonary receptors affect the secretion of ADH, which in turn influences urine flow. A subsequent investigation appeared to localize the pertinent receptors to the left atrium, but the results of this particular investigation were influenced by several complication factors that have not been widely appreciated. The apparent localization of volume-regulating recpetors to the left atrium and the accumulating evidence that atrial receptors do respond to changes in atrial pressure or atrial volume triggered a myriad of further studies on the function of left receptors. Nearly all these studies employed indirect techniques that produced changes in systemic and pulmonary hemodynamics in addition to changes in left atrial pressure. Nevertheless, it often was assumed that if changes in left pressure were produced, any concomitant changes in circulating ADH or in urine flow were attributable to a reflex elicited from atrial receptors. Mush of the data obtained were interpreted as being compatible with the elft atrial volume-receptor hypothesis, but very liggle of the data pertained to left atrial receptors specifically.

Sign in / Sign up

Export Citation Format

Share Document