AJP - Heart and Circulatory Physiology, Vol 249, Issue 6 1228-H1231, Copyright © 1985 by American Physiological Society
Effects of octanol on canine subendocardial Purkinje-to-ventricular transmission
R. W. Joyner and E. D. Overholt
The effects of 0.2 mM octanol on action potential propagation were
investigated using in vitro preparations of canine papillary muscles. In
these preparations an action potential initiated in the superficial
Purkinje (P) layer propagates across specific Purkinje-ventricular junction
(PVJ) sites into the underlying ventricular (V) layer. The conduction delay
at PVJ sites increased from 4.85 +/- 1.55 to 8.85 +/- 3.34 (mean +/- SD) ms
(n = 10, P less than 0.005), an 82% increase. However, propagation within
the V syncytium was much less affected, with a decrease of conduction
velocity by only 10% and a decrease in the maximal rate of rise of the
action potential of 23%. The results indicate that octanol, which has
previously been shown to increase gap junctional resistance, has a
preferential effect on PVJ sites, as predicted by the hypothesis that there
is a restricted pathway for intracellular current flow from P cells to V
cells at these sites.
