AJP - Renal Physiology, Vol 261, Issue 1 179-F186, Copyright © 1991 by American Physiological Society
Responses to renin inhibition in conscious primates
U. Humke, N. Levens, J. Wood and K. Hofbauer
Research Department, Ciba-Geigy, Basel, Switzerland.
A method for the measurement of renal clearances was adapted in a novel
manner to the conscious marmoset. Twenty-four hours before an experiment,
animals underwent surgery for placement of both femoral arterial and venous
catheters. A catheter was also implanted into the urinary bladder through
the abdominal wall. The urinary catheter consisted of two tubes. One tube
was connected to a pump, which removed the urine, while the other tube
remained open to prevent the formation of a vacuum inside the bladder.
Using this technique, we kept renal clearances stable for at least 3 h. All
catheters were removed the day after the clearance experiment, and the
bladder was reconstructed using microsurgical techniques. The bladder
operation did not appear to produce lasting anatomical or functional
changes, since the animals were able to void spontaneously and, after 3 mo,
the bladder had regained its normal size and shape. Reimplantation of both
the vessel and bladder catheters at this time allowed for an additional
study of renal clearances within the same animals. Administration of the
renin inhibitor CGP 29287 (1 mg/kg) to furosemide-pretreated conscious
marmosets lowered blood pressure and increased renal blood flow. Glomerular
filtration rate remained unchanged by CGP 29287, leading to a fall in the
effective filtration fraction. Urinary volume and urinary sodium excretion
also were unchanged by the renin inhibitor. We describe a novel method for
the study of renal clearances in a small conscious primate and suggest that
the renin-angiotensin system plays an important role in the control of
renal function in the sodium-depleted marmoset.
