抄録
The nervous control of the renal blood vessels were studied quantitatively in ‘spinal cord-renal nerve-kidney’ preparations of the toad following perfusion of its renal blood vessels with Ringer solution. The results obtained are summarized as follows.
1. When renal nerves were stimulated supraliminally electrically by square pulses, the rate of renal outflow decreased by about 90 per cent or more in ‘renal artery-renal vein system’ and by 33 per cent or less in ‘renal portal vein-renal vein system’. Dependence of the effect on each of the factors of the stimulating pulses (strength, duration and frequency) were studied separately and quantitatively. A vasoconstrictive substance could be detected in the perfusate of both system obtained during long lasting supraliminal stimulation of renal nerves. The effect of such perfusates tested on sino-atrial preparation of the toad was equivalent to 1.0μg/ml noradrenaline.
2. Renal nerves could be divided topographically into three groups. Each group innervates its own area of the renal vascular bed but there appears to be some overlapping.
3. Sectioning of the renal nerves produced an increase in the rate of outflow. Tonic discharges (1 to 4 impulses per second) could be recorded from the peripheral end of the nerves. These findings suggest a tonic innnervation through the renal nerves which contributes to renal vascular resistance.
4. Reflex vasoconstriction could be produced by the stimulation of the peripheral cut end of renal nerves in the ipsilateral side, but not in the contralateral.
5. The existence of vasodilator fibers in the renal blood vessels could not be demonstrated.Acetylcholine-like substance could not be detected in the perfusate obtained during stimulation of anterior root, posterior root and the vagus.
