Induced renal vasomotion in the intact dog

¹ University of Miami School of Medicine and Laboratories of Biochemistry, Howard Hughes Medical Institute, Miami, Florida

X-ray viewing of the opacified artery at a preselected interval before and after the administration of a pressor substance permits the study of induced vascular motion. This technique applied to the renal arteries of the dog demonstrated their extreme sensitivity to the catecholamines. With certain of these drugs, the effect persisted even after the return of the blood pressure to the control level. Two types of renal vascular responses occurred. One was characterized by an apparent increased resistance in the arteries distal to the third division and followed the administration of short-duration pressor compounds. The second type of response, occurring after the use of long-acting pressor compounds, was more general affecting all sizes of arteries, the divisions of the renal arteries being extraordinarily sensitive. Spinal cord damage, producing paraplegia, apparently reduced the renal vascular tone as the runoff of the radiopaque substance into the kidney was enhanced. This improved the clarity of the arteriograms. The induced vasodilation of the paraplegic animal was returned to the control state by the administration of epinephrine or norepinephrine.