The effect of stretching the superior vena caval—right atrial junction on right atrial receptors in the dog

Kappagoda, C. T.; Snow, H. M.

doi:10.1113/jphysiol.1972.sp010063

Cited by 35 publications

(29 citation statements)

References 7 publications

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“…Subsequently the dogs were anaesthetized with chloralose and artificially ventilated with oxygen-enriched air (approximately 40% 02) as described by Kappagoda, Linden & Snow (1972) and Kappagoda, Linden & Sivananthan (1979). The anaesthesia was maintained by a continuous infusion (0 5-1 0 mg. kg-min-') of the solution of chloralose in saline (1 g chloralose in 100 cm3 saline).…”

Section: Methodsmentioning

confidence: 99%

The Response in Efferent Cardiac Sympathetic Nerves to Stimulation of Atrial Receptors, Carotid Sinus Baroreceptors and Carotid Chemoreceptors

Mary

Weatherill

1982

Exp Physiol

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The reflex increase in activity in efferent cardiac sympathetic nerve fibres in response to distension of small balloons in the pulmonary vein‐atrial junctions was studied in dogs anaesthetized with chloralose; the carotid sinuses were isolated and perfused with blood. In the efferent cardiac nerves which responded to distension of the balloons there was no significant change in the control activity, or in the magnitude of the response during changes in carotid sinus pressure from 8 to 30 kPa, during changes in the blood perfusing the sinuses from arterial to venous or during stimulation of the cutaneous branch of the left radial nerve. In contrast, in efferent cardiac nerves which did not respond to the distension of the balloons, consistent and significant changes in activity resulted from stimulating arterial baroreceptors, chemoreceptors or a cutaneous branch of the radial nerve. It is concluded that efferent cardiac sympathetic nerve fibres which respond by an increase in activity to stimulation of the atrial receptors, constitute a group of nerve fibres which are separate from those responding to stimulation of receptors in the carotid region or to stimulation of peripheral somatic nerves.

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Section: Methodsmentioning

confidence: 99%

The Response in Efferent Cardiac Sympathetic Nerves to Stimulation of Atrial Receptors, Carotid Sinus Baroreceptors and Carotid Chemoreceptors

Mary

Weatherill

1982

Exp Physiol

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“…; the oesophageal temperature and pH, Pco0 and PO of arterial blood were monitored and maintained within normal limits using techniques described previously (Kappagoda, Linden & Snow, 1972). The reflex changes in heart rate in response to distension of the balloons, to changes in the pressure in the carotid sinuses, or to changes from arterial to venous in the nature of the blood perfusing the carotid sinuses were prevented by the administration of bretylium tosylate (dose 10 mg. kg-' i.v.)…”

Section: Methodsmentioning

confidence: 99%

The Responses in Renal Nerves to Stimulation of Atrial Receptors, Carotid Sinus Baroreceptors and Carotid Chemoreceptors

Mary

Weatherill

1981

Exp Physiol

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SUMMARYThe reflex reduction in activity in renal sympathetic nerves in response to distension of small balloons in the pulmonary vein-atrial junctions was studied in dogs anaesthetized with chloralose; the carotid sinuses were isolated and perfused with blood. In the first group of dogs, the response to distension ofthe balloons was studied at different levels ofcarotid sinus pressure. In thirteen preparations of renal nerves in eight dogs the response was not significantly influenced when the mean carotid sinus pressure was changed from 9 5 kPa to 17 5 kPa, despite marked changes in control frequencies of activity in the nerves. In the second group of dogs, the response to distension of the balloons was studied when the carotid sinuses were perfused alternately with arterial and venous blood. In six preparations of renal nerves in five dogs the response was not significantly influenced when the blood perfusing the carotid sinuses was changed, despite marked changes in control frequencies ofactivity in the nerves. In a third group of dogs, the reflex reduction in activity in renal nerves in response to a step increase in pressure in one carotid sinus was examined at different levels of pressure in the contralateral carotid sinus. In six preparations of renal nerves in five dogs the response to an increase in pressure in one carotid sinus was significantly reduced when the mean pressure in the contralateral sinus was changed from 8-7 kPa to 17 1 kPa. It is concluded that there is no interaction between the projections ofatrial receptors and carotid sinus baroreceptors or carotid chemoreceptors in their convergence on the same efferent renal neurones.

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“…On the other side, blood volume expansion activates atrial mechanoreceptors, with an increase of heart rate, inhibition of renal sympathetic nerve activity, and a decrease of vasopressin release (5,30). The reflex tachycardia in response to hypervolemia was first described by Bain-bridge in dogs (9), and it was also described in other species, including humans (10,12,34,62).…”

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Water deprivation increases Fos expression in hypothalamic corticotropin-releasing factor neurons induced by right atrial distension in awake rats

Benedetti

Rorato²,

Castro³

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

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LL. Water deprivation increases Fos expression in hypothalamic corticotropin-releasing factor neurons induced by right atrial distension in awake rats. Am J Physiol Regul Integr Comp Physiol 295: R1706 -R1712, 2008. First published September 10, 2008 doi:10.1152/ajpregu.00022.2008.-Atrial mechanoreceptors, sensitive to stretch, contribute in regulating heart rate and intravascular volume. The information from those receptors reaches the nucleus tractus solitarius and then the paraventricular nucleus (PVN), known to have a crucial role in the regulation of cardiovascular function. Neurons in the PVN synthesize CRF, AVP, and oxytocin (OT). Stimulation of atrial mechanoreceptors was performed in awake rats implanted with a balloon at the junction of the superior vena cava and right atrium. Plasma ACTH, AVP, and OT concentrations and Fos, CRF, AVP, and OT immunolabeling in the PVN were determined after balloon inflation in hydrated and water-deprived rats. The distension of the balloon increased the plasma ACTH concentrations, which were higher in water-deprived than in hydrated rats (P Ͻ 0.05). In addition, the distension in the water-deprived group decreased plasma AVP concentrations (P Ͻ 0.05), compared with the respective control group. The distension increased the number of Fos-and double-labeled Fos/CRF neurons in the parvocellular PVN, which was higher in the water-deprived than in the hydrated group (P Ͻ 0.01). There was no difference in the Fos expression in magnocellular PVN neurons after distension in hydrated and water-deprived groups, compared with respective controls. In conclusion, parvocellular CRF neurons showed an increase of Fos expression induced by stimulation of right atrial mechanoreceptors, suggesting that CRF participates in the cardiovascular reflex adjustments elicited by volume loading. Activation of CRF neurons in the PVN by cardiovascular reflex is affected by osmotic stimulation. cardiac reflex; paraventricular nucleus CHANGES IN BLOOD VOLUME OR arterial and venous pressure lead to activation of physiological responses to restore cardiovascular homeostasis. These responses involve regulatory adjustments that are detected by arterial baroreceptors and cardiopulmonary mechanoreceptors (19,53). Hemorrhage produces unloading of arterial baroreceptors that initiate a reflex response to increase the sympathetic vasomotor activity and vasopressin secretion (19,52). On the other side, blood volume expansion activates atrial mechanoreceptors, with an increase of heart rate, inhibition of renal sympathetic nerve activity, and a decrease of vasopressin release (5, 30). The reflex tachycardia in response to hypervolemia was first described by Bainbridge in dogs (9), and it was also described in other species, including humans (10, 12, 34, 62).The atrial mechanoreceptors are located at the venous-atrial junction of the heart, and it is continuously signaling the central venous volume to the brain. Through vagal afferent projections, the information from the atrial mechanoreceptors reaches the nuc...

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The effect of stretching the superior vena caval—right atrial junction on right atrial receptors in the dog

Cited by 35 publications

References 7 publications

The Response in Efferent Cardiac Sympathetic Nerves to Stimulation of Atrial Receptors, Carotid Sinus Baroreceptors and Carotid Chemoreceptors

The Response in Efferent Cardiac Sympathetic Nerves to Stimulation of Atrial Receptors, Carotid Sinus Baroreceptors and Carotid Chemoreceptors

The Responses in Renal Nerves to Stimulation of Atrial Receptors, Carotid Sinus Baroreceptors and Carotid Chemoreceptors

Water deprivation increases Fos expression in hypothalamic corticotropin-releasing factor neurons induced by right atrial distension in awake rats

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