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Primary neural involvement in renal haemodynamic and functional responses to prolonged stimulation of atrial receptors in anaesthetized dogs
Author(s) -
Majid DS,
Karim F
Publication year - 1995
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.1995.sp003873
Subject(s) - medicine , stimulation , endocrinology , kidney , renal blood flow , renal function , receptor , hemodynamics , reflex , renal physiology , chemistry
To determine the precise contributory role of neural and humoral factors in the efferent mechanism of the atrial receptor‐renal reflex, we have examined the effects of prolonged (45 min) stimulation of left atrial receptors on renal haemodynamics and function simultaneously in both kidneys (right kidney intact and left kidney denervated) of anaesthetized dogs. Aortic pressure in these dogs was held constant by means of an arterial reservoir connected to the aorta; heart rate changes were prevented by blocking beta 1‐adrenoceptor activity with atenolol (2 mg kg‐1 i.v.). Localized stimulation of atrial receptors in six dogs increased renal blood flow (6 +/− 2%), creatinine clearance (11 +/− 4%), urine flow (9 +/− 3%), sodium excretion (14 +/− 7%) and osmolal excretion (10 +/− 4%), and decreased free water clearance (14 +/− 7%) in intact kidneys, but led to no changes in denervated kidneys. In an additional four dogs, cooling the vagus nerves to 6–7 degrees C or cutting them in the neck abolished the renal responses to stimulation of atrial receptors in these stabilized preparations. These data clearly demonstrate that the renal responses to prolonged stimulation of atrial receptors are primarily mediated via myelinated vagal afferents and renal sympathetic efferents.