Relationship Between Right Atrial Stretch and Plasma Renin Activity
Stimulation of the right atrial receptors in rats attenuates both water and salt intake1,2. It would be reasonable to propose that this might be mediated by the renin-angiotensin system since there is evidence that, in dogs, increased left atrial stretch inhibits renin secretion3,4,5. However, the effects of right atrial stretch have been less convincing. Although Brennan6 et al found that right atrial stimulation did suppress PRA, Lee et al5 found that it was the left atrium which primarily influenced renin release. These experiments were carried out in dogs under very different conditions from those used in the studies on thirst and salt appetite. Therefore, it was decided to measure the changes in PRA using the same model as had been used to study ingestive behavior ie. inflation of a small balloon at the superior vena caval/right atrial junction in normovolaemic and hypovolaemic rats and after injection of the β -adrenergic agonist isoprenaline.
KeywordsPlasma Renin Activity Superior Vena Atrial Receptor Balloon Inflation Renin Release
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