Some Effects of Dihydrogenated Ergot Alkaloids on Renal Hemodynamics, Water and Electrolyte Excretion in the Dog

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Abstract
In dogs the hemodynamic effects of dihydrogenated ergot alkaloids (Hydergine or CCK) were contrary to those previously reported for dogs but confirmed those found in man, viz., reduction in renal plasma flow and elevation of filtration fraction with little or no change in glomerular filtration rate. In anesthetized dogs with one kidney denervated, the reduction in renal plasma flow was Usually more pronounced in the denervated kidney. CCK increased Na excretion in unanesthetized dogs only in the hydropenic state. This effect was also noted in an adrenalectomized dog. Under pentobarbital anesthesia CCK admn. was associated with increased Na excretion regardless of exptl. conditions, with the exception of renal denervation. Further, the reduction in Na excretion associated with direct stimulation of the splanchnic nerve could be abolished by prior medication with CCK. It was concluded that, as in other circulations, the dihydrogenated ergot alkaloids act on the renal circulation in 2 ways, by direct vasoconstriction, and by peripheral blockade of sympathetic impulses. The former action predominates, particularly in the denervated kidney. It is suggested that the natriuretic effect of CCK may result from peripheral blockade of sympathetic impulses and that this effect may be independent of the hemodynamic effect.