Regional myocardial interstitial norepinephrine kinetics during
coronary occlusion and reperfusion.
Shindo, Tetsuaki, Tsuyoshi Akiyama, Toji Yamazaki, and Ishio Ninomiya.
Department of Cardiac Physiology, National Cardiovascular Center
Research Institute, Suita, Osaka 565, Japan
APStracts 2:0287H, 1995.
We investigated myocardial interstitial norepinephrine kinetics in
both the ischemic and non-ischemic regions during reperfusion
following 40 min coronary occlusion in anesthetized cats. Using a
cardiac dialysis technique, dialysate norepinephrine contents from
both regions were monitored as an index of myocardial interstitial
norepinephrine levels. Vehicle perfusate (n=8): The accumulated
dialysate norepinephrine level in the post-ischemic region decreased
from 3010+/-923 pg/ml at 30-40 min of occlusion to 957+/-178 pg/ml at
0-10 min of reperfusion and returned to near the control level at 30
-40 min of reperfusion. After 40 min of reperfusion, there were no
significant differences in tyramine (100 [mu]g/ml, norepinephrine
-releasing sympathomimetic amine)-induced norepinephrine releases
between the both two regions. Perfusate containing 100[mu]M
desipramine (neural uptake inhibitor, n=6): At 0-10 min of
reperfusion, the dialysate norepinephrine in the post-ischemic region
did not significantly decrease. Then the dialysate norepinephrine
returned to near the pre-occlusion level at 30-40 min of reperfusion.
These data suggest that reperfusion rapidly returns accumulated
myocardial norepinephrine to the pre-ischemic level and neuronal
norepinephrine uptake greatly contributes to this return in the early
phase of reperfusion. Forty min coronary occlusion causes neither
norepinephrine exhaustion nor irreversible impairment of
norepinephrine uptake function in nerve terminals.
Received 26 October 1994; accepted in final form 16 June 1995.
APS Manuscript Number H950-4.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 18 July 1995.