Renal blood flow, glomerular filtration rate, renal PAH extraction ratio, and the role of the renal vasomotor nerves in the unanesthetized rabbit.

• The rabbit offers some advantages as an unanesthetized preparation over other species, in that it will, remain quietly, without previous training, in a small cage during a variety of experimental procedures. Previous work from this laboratory has shown that the circulation of the rabbit studied under these conditions is stable as judged by the relative constancy of the resting cardiac output, blood pressure and heart rate over a period of hours. The variability of these measurements was similar to that observed in man or the dog. However, a number of workers have considered the renal circulation of the rabbit to be less stable than that of other species," and the rabbit has not been widely used for renal circulatory studies. On the other hand, Forster, and Brod and Sirota obtained reasonable degrees of rcproducibility of renal blood flow and glomerular filtration rate in unanesthetized lightly restrained rabbits. In its response to water loading the renal circulation of the rabbit is said to resemble that of marine mammals and amphibia and to differ from that of man and the dog.' '"• "