Abstract
In order to elucidate the relation of the ureteral motility to ureteral ganglion cells, the ureteral lumen of dogs anesthetized with pentobarbital sodium is perfused with saline solution, or with the saline solution to which acid or alkali is added in various concentrations.
1. In the orthodromic perfusion the following facts are noted:
a) When the counter pressure is kept constant, the outflow volume per unit time interval increases with increase in the pressure gradient.
b) When the counter pressure is lower than a certain critical point, the pressure gradient just necessary enough to produce the outflow, i. e. the threshold pressure gradient, is lowered with increase in the counter pressure. Besides, at the same pressure gradient, the higher the counter pressure is, the greater the amount of the outflow volume.
c) When the counter pressure rises beyond a critical pressure, there occurs a retardation of the flow, which then becomes more and more distinct with further increase in the counter pressure, threshold pressure gradient tending to become higher again. After all it may be concluded that with increase in the counter pressure the caliber of the ureter is widened gradually until a certain critical pressure is reached, and then narrowed again when the pressure is further increased beyond the critical point.
2. In the condition where both the counter pressure and the pressure gradient are within the moderate range, the flow instantaneously stops when the direction of the perfusion is reversed. It is observed that, while the flow stops, the lower part of the ureter falls into a persistent contraction superimposed with pulsations that propagate as waves both up- and downwards.
3. Comparing the results described above with those obtained in the perfusion experiment of the small intestine, it can be concluded that the ureteral ganglion cells have no particular function in the ureteral motility, and that the change of the ureteral motility observed in the ortho- and antidromic perfusion of the ureteral lumen is entirely of myogenic origin.
