Neural Influences on Bullfrog Renal Functions

Abstract

Abstract

The present investigations suggest that α-adrenergic mechanisms may be involved in the control of glomerular and tubular functions of bullfrog kidneys. Hypothalamic lesions did not appreciably affect the antidiuretic response of bullfrogs to dehydration. Phenoxybenzamine reversed the antidiuresis in dehydrated intact bullfrogs. We also performed experiments in which bullfrog kidneys were perfused through the dorsal aorta and renal portal veins in situ. In such perfused kidneys, the renal portal perfusate did not reach the glomeruli. Phenoxybenzamine applied to the arterial perfusate blocked the antidiuretic effect of norepinephrine and produced diuresis and increased renal perfusion. The same response was observed with pithing or destruction of the spinal cord and central nervous system. Phenoxybenzamine given through the left renal portal perfusion would reach the tubules of the left kidney. It produced diuresis and natriuresis in the treated kidney but not the right control kidney. We conclude that neural activities influence preglomerular vasoconstriction and tubular reabsorption in bullfrogs.