Wjep. Lammers et al., SPATIAL AND TEMPORAL VARIATIONS IN PACEMAKING AND CONDUCTION IN THE ISOLATED RENAL PELVIS, American journal of physiology. Renal, fluid and electrolyte physiology, 39(4), 1996, pp. 567-574
In renal pelvis preparations isolated from the sheep, the location of
the pacemaker and the pathway of conduction of the electrical impulse
in the pelvis were analyzed in detail. An electrophysiological acquisi
tion system was used allowing simultaneous recordings from 240 extrace
llular electrodes. Reconstruction of the spread of activity showed tha
t the site of the pelvis pacemaker was, in virtually all cases, locate
d at the pelvicalyceal border and never in the body of the pelvis or i
n the area of the pelviureteric junction. One single pacemaker was res
ponsible for a particular spread of activation, and fusion of activity
originating from two or more pacemakers did not take place. Furthermo
re, spontaneous shifts of the pacemaker could occur from one site to a
nother along the pelvicalyceal border. Conduction from the site of the
current pacemaker to the pelviureteric junction and the ureter was sl
ow, inhomogeneous, and contorted. Multiple instances of partial or tot
al conduction block were seen at all levels in the pelvis and were not
restricted to the pelviureteric junction. The occurrence of conductio
n block did not seem to be related to the length of the preceding inte
rval, implying that the refractory period did not play a major role in
the genesis of intrapelvic conduction block. In conclusion, high-reso
lution mapping of the renal pelvis is possible and reveals location an
d behavior of the pacemaker and documents inhomogeneities in conductio
n and conduction block.