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Renal Responses to atrial stretch and acute volume expansion in the rat

Zhao Gong, Ho Shiuyong

Department of Physiology, Institute of Basic Medicine, Hebei Medical College. Hebei, China

Abstract

Effects of atrial stretch and acute volume expansion on the urine flow, urinary
sodium and potassium were studied in 28 anesthetized rats. When the right atrium
was stretched with a weight of 5-7 g for 30 min, the urine flow, urinary sodium and potassium excretion were increased respectively by 98%, 12.7% and 59% in the intact rats (n=6). These renal responses were not affected by vagotomy. Similar renal responses could be produced by stretching the left atrium of the intact rats (n=4). Effect of ligation of the right appendage on the renal response to acute volume expansion was examined in vagotomized rats. In the sham-operated rats (n=6), acute volume expansion induced a significant diw-esis, natriuresis and kaliuresis. In the rats with ligation of the right appendage, the natriuretic response was decreased to only one-half of that in the sham-operated rats, while the diuretic and kaliuretic effects showed no significant changes. The renal responses to atrial stretch and acute volume expansion could not be attributed to the reflex of volume receptors since they were not affected by bilateral vagotomy. Thus the abovementioned results suggest that atrial stretch and acute volume expansion may induce release of endogenous atrial natriuretic factor from the atrium, which is reduced by ligation of the right appendage.

Key words: Atrial natriuretic factor;Urine volume;Urinary sodium excretion;Atrial stretch;Acute volume expansion

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Citing This Article：

Zhao Gong, Ho Shiuyong. Renal Responses to atrial stretch and acute volume expansion in the rat. Acta Physiol Sin 1987; 39 (5): (in Chinese with English abstract).