TITLE

NERVOUS CONTROL MECHANISM OF THE RENAL VASCULAR TONE

AUTHOR(S)
Yamagishi, Shunichi; Azuma, Takehiko
PUB. DATE
November 1965
SOURCE
Angiology;Nov1965, Vol. 16 Issue 11, p705
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The control of renal vascular tone by the nervous mechanism was investigated with the perfused renal nerves (kidney preparation) of toads. Results obtained were summarized as follows. 1. Pressure-flow diagram became linear in the perfusion pressure range of higher than 40 cm H2O. In the lower range, the diagram was convexed toward the pressure axis. The flow ceased at the perfusion pressure of 5 cm H2O. This value could be considered as ‘critical closing pressure.’ 2. Stimulation of the renal nerves with electric current of square wave pulses reduced the rate of renal outflow at every perfusion pressure, so that the pressure-flow curve thus depicted shifted to the right. The gradient of linear part of the curve was equal to that of the curve obtained without the nerve stimulation. The critical closing pressure was always higher than 5 cm H2O. 3. The rate of flow at a given perfusion pressure was always reduced by changing the perfusion fluid from Ringer's solution to noradrenaline-Ringer's solution of various concentrations. At a given perfusion pressure, the slope of the pressure-flow curve obtained by perfusion with noradrenaline-Ringer's solution grew smaller with an increase in the concentration of noradrenaline used. 4. The amount of the reduction in the ‘effective radius’ of imaginary equivalent unit vessel induced by the nerve stimulation decreased with an increase in perfusion pressure. On the other hand, the amount of the reduction brought about by perfusing the preparation with noradrenaline-Ringer's solution of a certain fixed concentration was constant in wide range of perfusion pressure. 5. The active tension of the wall of the imaginary equivalent unit vessel developed by the nerve stimulation and the administration of noradrenaline increased in proportion to the increase in the intravascular pressure. Therefore, the smooth muscle in the wall of the vessel is considered to be able to develop enough active tension to overcome the applied intravascular pressure and to shorten the radius by the same amount regardless of the intravascular pressure. 6. The rate of discharge of the vasoconstrictive transmitter from nerve endings produced by the supraliminal nerve stimulation was estimated experimentally to be constant. The concentration of the transmitter in perfusate was determined by the rate of perfusion.
ACCESSION #
16372492

 

Related Articles

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics